Plants of the Nyika Plateau

Plants of the Nyika Plateau i

Recommended citation format BURROWS, J.E. & WILLIS, C.K. (eds) 2005. Plants of the Nyika Plateau: an account of the vegetation of the Nyika National Parks of Malawi and Zambia. Southern African Botanical Diversity Network Report No. 31. SABONET, Pretoria. Produced and published by Southern African Botanical Diversity Network (SABONET) c/o South African National Biodiversity Institute, Private Bag X101, 0001, Pretoria Printed in 2005 in the Republic of South Africa by Capture Press, Pretoria, (27) 12 349-1802 ISBN 1-919976-08-6 © 2005 SABONET. All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means without the permission of the copyright holder.

Editor-in-chief: Marthina Mössmer Subeditors: Lidia Gibson & Hanlie van Heerden Indexing: Marthina Mössmer & Martin Mössmer Text design and layout: Antoinette Burkhardt Cover design: Antoinette Burkhardt, Pretoria, South Africa (27) 83 6351446. Front cover: Top: Lake Kaulime (C. Willis). Bottom, left to right: Vittaria guineensis var. orientalis (J. Burrows); Disa ukingensis (H. Kurzweil); Delphinium leroyi (J. Burrows); Streptocarpus wittei (W. Pawek); Scadoxus multiflorus subsp. multiflorus (J. Burrows). Back cover: Impressions of Nyika (W. Pawek). Spine: Impatiens tinctoria subsp. latifolia (J. Burrows). SABONET website: www.sabonet.org

This report is a product of the Southern African Botanical Diversity Network (SABONET) and was made possible through support provided by the Global Environment Facility (GEF)/United Nations Development Programme (UNDP) and the United States Agency for International Development (USAID)/World Conservation Union-Regional Office for southern Africa (IUCN ROSA) (Plot no. 14818 Lebatlane Road, Gaborone West, Extension 6 Gaborone, Botswana), under the terms of Grant No. 690-0283-A-00-5950. The opinions expressed herein are those of the authors and do not necessarily reflect the views of GEF/UNDP, USAID/IUCN ROSA, the SABONET Steering Committee or SABONET National Working Groups.

ii Plants of the Nyika Plateau

Plants of the Nyika Plateau An account of the vegetation of the Nyika National Parks of Malawi and Zambia

Edited by John E. Burrows & Christopher K. Willis

2005 Southern African Botanical Diversity Network Report No. 31 Plants of the Nyika Plateau iii

Contents Contributors .......................................................................................................................... viii Foreword ................................................................................................................................. ix Preface ..................................................................................................................................... x Abbreviations and acronyms ................................................................................................... xi Herbarium acronyms ............................................................................................................... xi Acknowledgements ............................................................................................................... xiii Introduction.............................................................................................................................. 1 Climate............................................................................................................................... 2 Drainage and soils .............................................................................................................. 3 Landslips ............................................................................................................................ 3 Fire ..................................................................................................................................... 4 Vegetation communities ..................................................................................................... 4 Plant diversity ..................................................................................................................... 9 Endemism........................................................................................................................... 9 Botanical exploration of the Nyika Plateau ............................................................................. 11 Species accounts .................................................................................................................... 19 Anthocerotophyta ............................................................................................................. 20 Hepatophyta ..................................................................................................................... 20 Bryophyta ......................................................................................................................... 21 Pteridophyta ..................................................................................................................... 25 Gymnosperms .................................................................................................................. 46 Dicotyledons .................................................................................................................... 48 Monocotyledons............................................................................................................. 287 Glossary ............................................................................................................................... 369 References and further reading ............................................................................................. 376 Photo credits ........................................................................................................................ 382 Collectors’ index .................................................................................................................. 383 Index to common names ...................................................................................................... 384 Index to scientific names ...................................................................................................... 387

Plants of the Nyika Plateau vii

Contributors John Burrows Buffelskloof Herbarium, Lydenburg Scientific editor and species treatments for all families, except those listed below. Lyn Fish National Herbarium, South African National Biodiversity Institute, Pretoria Poaceae, Cyperaceae, Commelinaceae Marinda Koekemoer National Herbarium, South African National Biodiversity Institute, Pretoria Asteraceae, Bryophyta Hubert Kurzweil Compton Herbarium, South African National Biodiversity Institute, Cape Town Orchidaceae Graham Williamson Orchidaceae Christopher Willis South African National Biodiversity Institute, Pretoria Introduction and Botanical Exploration Pieter Winter National Herbarium, South African National Biodiversity Institute, Pretoria (formerly of University of the North Herbarium, Polokwane) Acanthaceae, Apiaceae, Crassulaceae, Lamiaceae Illustrators Sandie Burrows (principal illustrator) Charmaine Bartman Auriol Batten Eleanor Catherine Maureen Church Derek Erasmus Victoria Friis (Goaman) Christine Grey-Wilson Mary Grierson Pat Halliday Cythna Letty Julia Loken John Manning Wilma Roux Clare Smith Margaret Tebbs William Trevithnick H. Wouda-du Toit Graham Williamson Heather Wood

viii Plants of the Nyika Plateau

Abbreviations and acronyms AETFAT aff. alt. auctt. BP C.A.R. ca cf. coll. CSIR CUSO Del. D.R.C. E. et al. F.T.A. F.T.E.A. F.Z. GEF holo. ibid. iso. IUCN lecto. loc.cit. LUOTC ms. N. nom. alt. nom. cons. nom. illeg. nom. nudum S. s.n. SABONET SAC sp. spp. SUOTC syn. UNDP W. WWF

Association pour l’Etude Taxonomique de la Flore d’Afrique Tropical (Association for the Taxonomic Study of the Flora of Tropical Africa) affinis, affiliated to, bordering altitude auctorum, of authors, implying in common usage before present Central African Republic circa, about, roughly confer, compare with collegit, he gathered, collected by Council for Scientific and Industrial Research Canadian University Service Overseas Delineavit, drawn by Democratic Republic of Congo (formerly Zaire) east, eastern (in species lists) et alii, and others Flora of Tropical Africa Flora of Tropical East Africa Flora zambesiaca Global Environment Facility holotype ibidem, in the same place isotype The World Conservation Union lectotype loco citato, at the place cited, usually implying “cited above” Leeds University Officer Training Corps manuscript north, northern (in species lists) nomen alternativum, an alternative name nomen conservandum, conserved name nomen illegitimum, illegitimate name nomen nudum, name published without a description south, southern (in species lists) sine numero, without a number Southern African Botanical Diversity Network Satellite Application Centre species, singular species, plural Southampton University Officer Training Corps syntype United Nations Development Programme west, western (in species lists) World Wide Fund for Nature

Herbarium acronyms Herbarium acronyms follow Holmgren, Holmgren & Barnett (1990) and Smith & Willis (1999). A

Herbarium, Arnold Arboretum, Harvard University, Cambridge, Massachusetts, U.S.A. Plants of the Nyika Plateau xi

B BM BOL BR BRLU C CAH COI DAV DBN DSM E EA FHO FRIM GA J K LISC LMA LMJ M MA MAL MO MPR MU NBG NDO NH NU NY OXF P PRE RNG S SAM SCHG SRGH UC UMO UNIN UPS US UT UZL WAG WU

Herbarium, Botanischer Garten und Botanisches Museum Berlin-Dahlem, Berlin, Germany Herbarium, Botany Department, The Natural History Museum, London, England, U.K. Bolus Herbarium, Botany Department, University of Cape Town, Cape Town, South Africa Herbarium, Nationale Plantentuin van België, Jardin Botanique National de Belgique, Domein van Bouchout, Meise, Belgium Herbarium, Laboratoire de Botanique Systématique et de Phytosociologie, Université Libre de Bruxelles, Bruxelles, Belgium Herbarium, Botanical Museum, University of Copenhagen, Copenhagen, Denmark Herbarium, Department of Biological Sciences, University of Zimbabwe, Harare, Zimbabwe Herbarium, Botanical Institute, University of Coimbra, Coimbra, Portugal John M. Tucker Herbarium, Botany Department, University of California, Davis, California, U.S.A. Herbarium, National Botanic Gardens, Glasnevin, Dublin, Ireland Herbarium, Botany Department, University of Dar es Salaam, Dar es Salaam, Tanzania Herbarium, Royal Botanic Garden, Edinburgh, Scotland, U.K. Herbarium, National Museums of Kenya, Nairobi, Kenya Daubeny Herbarium, Plant Sciences Department, University of Oxford, England, U.K. Forestry Research Institute of Malawi, Zomba, Malawi Herbarium, University of Georgia, Athens, Georgia, U.S.A Charles E. Moss Herbarium, Botany Department, University of the Witwatersrand, Johannesburg, South Africa Herbarium, Royal Botanic Gardens, Kew, England, U.K. Herbário, Centro de Botânica, Instituto de Investigação Científica Tropical, Lisbon, Portugal Herbarium, National Institute for Agronomic Research, Maputo, Mozambique Herbarium, Botanical Department of the Cotton Research Centre, Maputo, Mozambique. LMJ transferred to LMA. Herbarium, Botanische Staatssammlung, München, Germany Herbario, Real Jardín Botánico, Madrid, Spain National Herbarium, Zomba, Malawi Herbarium, Missouri Botanical Garden, Saint Louis, Missouri, U.S.A. Herbarium, National Plant Genetic Resources Centre, Mount Makulu Central Research Station, Chilanga, Zambia Herbarium, Botany Department, Miami University, Oxford, Ohio, U.S.A. Compton Herbarium, South African National Biodiversity Institute, Cape Town, South Africa Herbarium, Division of Forest Research, Forestry Department, Kitwe, Zambia KwaZulu-Natal Herbarium, South African National Biodiversity Institute, Durban, South Africa Herbarium, Botany Department, University of KwaZulu-Natal, Pietermaritzburg, KwaZulu-Natal, South Africa Herbarium, New York Botanical Garden, Bronx, New York, U.S.A. Fielding-Druce Herbarium, Plant Sciences Department, University of Oxford, Oxford, England, U.K. Herbier, Laboratoire de Phanérogamie, Muséum National d’Histoire Naturelle, Paris, France National Herbarium, South African National Biodiversity Institute, Pretoria, South Africa Herbarium, Plant Science Laboratories, University of Reading, Whiteknights, Reading, Berkshire, England, U.K. Herbarium, Botany Departments, Swedish Museum of Natural History, Stockholm, Sweden South African Museum Herbarium, Cape Town, South Africa; maintained as a separate entity within the Compton Herbarium (NBG), South African National Biodiversity Institute, Cape Town, South Africa Southern Cape Herbarium, George, South Africa National Herbarium (and Botanic Garden), Causeway, Harare, Zimbabwe University Herbarium, University of California, Berkeley, California, U.S.A. Herbarium, Biological Sciences Division, University of Missouri, Columbia, Missouri, U.S.A. University of the North Herbarium, Polokwane, South Africa Botanical Museum (Fytoteket), Uppsala University, Uppsala, Sweden United States National Herbarium, Botany Department, Smithsonian Institution, Washington, D.C., U.S.A. Garrett Herbarium, Utah Museum of Natural History, University of Utah, Salt Lake City, Utah, U.S.A. University of Zambia Herbarium, Lusaka, Zambia Herbarium Vadense, Department of Plant Taxonomy, Agricultural University, Wageningen, Netherlands Herbarium, Institut für Botanik, Universität Wien, Wien, Austria

xii Plants of the Nyika Plateau

Foreword I feel very honoured to have been asked by Christopher Willis, chief organiser of the SABONET Nyika Plateau Expedition in 2000, to provide a foreword for Plants of the Nyika Plateau. This book will be a valuable reference work for biodiversity managers, planners, academics, researchers, decision-makers, NGOs, and local communities. The Nyika Plateau is a unique ecosystem for the survival of old plants and birth of new ones. Over millennia, the mixture of both old and new plant species has resulted in unique plant diversity, making the Nyika Plateau one of the world’s hotspots or important plant areas. A new visitor to Nyika is always greeted on the main plateau by the beauty of the rolling grasslands with dotted outcrops of varied forests, hills, and mountaintops. Of course to the tourist, this is just another place for recreation, while the local people regard the Nyika Plateau as a source of clean water and valuable non-timber products; but to the biologist, that beauty, both at species and habitat level, becomes a big attraction for scientific inquiry. Thus, the rich plant diversity of the Nyika Plateau has been a subject of research for botanists over the years, and the SABONET Nyika Plateau Expedition and its resultant publication are commendable developments that will improve our knowledge about the plants of the Nyika Plateau. The SABONET Nyika Plateau Expedition was one of the main capacity-building activities of the SABONET project; a similar collecting expedition was undertaken to southern Mozambique in 2001. The expedition was notable since it was organised from within the sub-region, and was attended by 24 participants from six countries in southern and eastern Africa (Malawi: 7, Mozambique: 1, South Africa: 9, Zambia: 4, Zimbabwe: 2 and Tanzania: 1). The participation of both veteran and young botanists from the region enriched the expedition and made it unique. The collection of 3,343 plant specimens is a remarkable achievement. The description of one new species, many new plant distribution records, and the identification of several rare species are indications of the international botanical importance of the Nyika Plateau. I have no doubt that the Nyika Plateau provided a natural theatre and laboratory where veteran botanists such as Augustine Salubeni, Hassam Patel, Leonard Mwasumbi, John Burrows, and Patrick Phiri, amongst others, taught their young colleagues many aspects of field botany and plant taxonomy, including collection techniques, field identifications, character recognition of major plant groups, Nyika Plateau endemics, and rare plants. The great plant diversity of the Nyika Plateau must indeed have re-affirmed and demonstrated once again to the expedition members the concept of a “hotspot”. In addition, the Nyika Plateau must have shown the unique distribution patterns of some plants, such as the pencil cedar, whose disjunct southern distribution appears to end at the Plateau. The botanical survey of many developing countries remains poor mainly owing to lack of financial resources for fieldwork. This insufficient knowledge about the botany of our plants will impede the implementation of international obligations (such as the Convention on Biological Diversity, Wetland Convention—RAMSAR, and Millennium Development Goals) that aim to assist our governments to achieve sustainable development. However, for the ten southern African countries, the GEF/UNDP and USAID/IUCN ROSA funding of the SABONET project has meant enhancement of scientific and technical co-operation on plant diversity. In particular, building a team of experts from the region to collect, identify, document, and publish Plants of the Nyika Plateau shows that, given adequate funding, Africa has the human capacity to document every plant in our respective countries. Certainly, the Nyika Plateau team should not rest, but use the Nyika Plateau experience to penetrate and botanise other important under-collected habitats in our sub-region. They should form a long-lasting human network on which the region will rely for solving botanical and taxonomic problems at both the national and regional level.

Professor J.H. Seyani General Manager & Chief Executive National Herbarium and Botanic Gardens of Malawi

Kasyaula Forest (Malawi)

Manyenjere Forest (Zambia) Plants of the Nyika Plateau ix

Preface For in order to care deeply about something important it is first necessary to know about it. So let us resume oldfashioned expeditions at a quickened pace, solicit money for permanent field stations, and expand the support of young scientists—call them “naturalists” with pride—who by inclination and the impress of early experience commit themselves to deep knowledge of particular groups of organisms. —E.O. Wilson, “On the future of conservation biology” This book represents our current knowledge and understanding of the diversity of plants found on the Nyika Plateau, and draws on both published and unpublished information. The checklist was started in 1999, to aid plant collectors on a SABONET-funded regional plant collecting expedition to the Nyika Plateau in March–April 2000; subsequently, the list has been refined, based on the collections made during the expedition. One of our main aims was to make the final publication as useful to as broad an audience as possible. It had to be accessible, not only to taxonomists and plant diversity specialists, but also to research staff working in the Nyika National Parks and tourists interested in the Nyika Plateau’s plant diversity. To this end, an illustration of every plant genus in the list has been included, making the task of identification easier. Where possible, diagnostic characters of specific genera have been indicated in the drawings. Photographs of landscapes and plants will assist readers in recognising some of the Nyika Plateau’s diverse landscapes, habitats, and flowering plants. We believe that this publication will make a significant contribution towards documenting the Nyika Plateau’s diverse floral heritage. It is a continuation of work done by botanists and plant collectors, some more than a century ago. We recognise that this checklist may be incomplete, and trust that it will be expanded and improved upon as knowledge of the Nyika Plateau flora increases. Furthermore, it is our hope that this checklist will be used to assist conservation authorities and planners in safeguarding the Nyika Plateau’s flora and its associated life forms for both present and future generations.

John Burrows Christopher Willis

Nkhonjera Hill x Plants of the Nyika Plateau

Acknowledgements This publication would not have been possible without the tremendous efforts of the SABONET publication and editorial team—Marthina Mössmer, Lidia Gibson, Hanlie van Heerden, and Antoinette Burkhardt. We thank them sincerely for their patience and professional approach towards the compilation of this book. Sandie Burrows prepared the majority of the line drawings. The many hours spent illustrating the various Nyika plant genera are greatly appreciated. We also thank Sandie for her help and support during the SABONET Nyika Expedition in March–April 2000. Generous financial support and sponsorship from the GEF/UNDPfunded Southern African Botanical Diversity Network (SABONET) Project made this book possible. We thank the Chairman (Prof. Brian Huntley) and members of the SABONET Steering Committee, particularly Patrick Phiri, Dickson Kamundi, and Augustine Chikuni, for their ongoing support of and enthusiasm for the Nyika expedition and the development of this publication. Co-funding from the Wildlife Conservation Society in Tanzania facilitated the participation of Leonard Mwasumbi from the University of Dar-es-Salaam in the Expedition. We are grateful to the members of the SABONET Secretariat for their administrative and logistical support that made both the Expedition and the book possible: Stefan Siebert, Yolande Steenkamp, Nyasha Rukazhanga-Leboho (née RukazhangaNoko), Carina Haasbroek, Lorna Davis, and Elsabe Malan. Thank you also to Leanna Els (South African National Biodiversity Institute, Pretoria) for administrative assistance. Prior to the regional expedition the Royal Geographical Society’s Expedition Advisory Centre (London, U.K.) provided valuable advice, literature, and support. We would specifically like to thank members of the SABONET Nyika Expedition for their tremendous enthusiasm and efforts in the field, and also for processing their specimens after the Expedition. Malawi: Humphrey Chapama (87 specimens), Augustine Chikuni (24), Crispin Kasakula (72), Montfort Mwanyambo (102), Hassam Patel (72), Augustine Salubeni (91), and Moffat Thera (115); Mozambique: Samira Izidine (142); Zambia: Patrick Phiri (548), Ashed Makukula (136), Annaniah Sakala (101), and Wilfred Moonga (135); South Africa: Sandie Burrows (214, with John Burrows), Lyn Fish (204), Marinda Koekemoer (244), Solomon Nkoana (110), Hubert Kurzweil (81), Christopher Willis (255), Pieter Winter (254), and Steve Johnson (no plant specimens collected); Zimbabwe: Alfred Maroyi (94) and Ratidzayi Takawira (155); Tanzania: Leonard Mwasumbi (107). Many taxonomic specialists assisted in the identification of specimens from the Expedition. The following individuals are thanked for coordinating the completion of various family treatments listed in this checklist. Lyn Fish (PRE) provided the Poaceae, Cyperaceae, and Commelinaceae; Marinda Koekemoer (PRE) provided the Asteraceae and Bryophyta; Hubert Kurzweil (NBG) and Graham Williamson provided the Orchidaceae, and Pieter Winter (PRE, previously at UNIN) provided the treatments of the families Acanthaceae, Apiaceae, Crassulaceae, and Lamiaceae. We also acknowledge the following taxonomists who provided valuable taxonomic advice and support in the treatment of various plant groups: René Glen (PRE; aquatics), David Goyder (Kew; Apocy-

naceae), Robert Faden (Botany Department, Smithsonian Institution, Washington DC, U.S.A.; Commelinaceae), Clare Archer (PRE; Cyperaceae), Robert Archer (PRE; Celastraceae), Marie Jordaan (PRE; Celastraceae), Serena Marner (OXF; Faurea), Kevin Balkwill (Botany Department, University of Witwatersrand; Acanthaceae), Diane Bridson (Kew; Rubiaceae), Henk Beentje (Kew; Helichrysum), Tom Cope (Kew; Poaceae), Yvette Harvey (Kew; Leonotis), Roger Polhill (Loranthaceae), and Alan Paton (Kew; Lamiaceae). Janice Golding assisted with the compilation of the section on the endemic plants of the Nyika Plateau. We acknowledge the following people for use of their slides and images: Hubert Kurzweil, Serena Marner, Alan Paton, Mike Meadows, Hugh Synge, Graham Williamson, Bryan Simon, Bruce Hargreaves, Roger Polhill, Dick Brummitt, William and Jean Pawek, Gerald Pope, David Goyder, Isobyl la Croix, Audrey Moriarty, Bob and Françoise Dowsett-Lemaire, Norman Robson, and Jim Chapman. Hassam Patel (Malawi) provided determinations for the specimens collected by Samira Izidine (Mozambique) on the Expedition. Hassam visited the LMA Herbarium (Maputo, Mozambique) from 12–20 November 2001 through an internship supported by the SABONET Project. We thank Peter and Marianne Overton of Biosearch Nyika for their cooperation and the use of their plant checklists compiled over several years of collecting expeditions to various parts of the Nyika National Park. We are grateful to Dick Brummitt (with Gerald Pope) for providing the section on Alexander Whyte’s travels, as well as the locality information of Adiantum reniforme in the Wovwe River, Nyika National Park. This enabled the Expedition team to collect the plant 28 years after it was first discovered and collected by the Wye College (University of London) Expedition in 1972. Hugh Synge kindly supplied us with a copy of the final report from the Wye College 1972 Malawi Project. The Nyika and Malawi National Parks staff, particularly Gibson Mphepo, Muteto Dlamini, Paul Chisambo, and Jonas Luhanga offered support, companionship, and advice during the regional collecting expedition. Thanks to Kit Cottrell (Entomology Department, Kutsaga Research Station, Harare, Zimbabwe) for earlier discussions and enthusiastic support for the SABONET Nyika Expedition. Ian Thomson, of the Nyika Vwaza Conservation Project, northern Malawi, gave advice and suggestions prior to the Expedition. Alan Paton (Royal Botanic Gardens, Kew) obtained addresses and contact details of artists who contributed to published volumes of Flora zambesiaca. The Flora zambesiaca Management Committee generously provided a complete set of Flora zambesiaca volumes to the SABONET Secretariat for use as reference material during the Expedition and for subsequent expeditions and training courses. Estelle Potgieter and Anne-Lise Fourie of the Mary Gunn Library, National Herbarium, Pretoria, tracked down various publications and reference materials used in this book. Emsie du Plessis, of the South African National Biodiversity Institute’s Publications Section in Pretoria, edited earlier versions of the References section.

Plants of the Nyika Plateau xiii

Hugh Glen and Gerrit Germishuizen (PRE) provided assistance with notes and photographs of early plant collectors on the Nyika Plateau. Photographs of early collectors on the Nyika Plateau were also received from the Royal Botanic Gardens, Kew (Kate Pickard and James Kay), and the Hunt Institute for Botanical Documentation, Carnegie Mellon University, Pittsburgh, U.S.A. (Angela Todd and Lisa Ferrugia). Rodney Moffett brought to our attention some infelicities in the species list. John Nkhoma (Regional Geologist, Mzuzu, Malawi) furnished us with geological maps of the Nyika Plateau during our reconnaissance expedition (May 1999) to the Nyika National Park. The personnel of the Nyika Safari Company, particularly David and Robyn Foot, and Gary and Fiona Brown, are thanked for their warm hospitality and support at Chelinda Camp, Nyika National Park, during both the reconnaissance and the main expedition. The satellite (LANDSATTM) image-map of the Nyika Plateau, dated 18 September 1995, was generated by the Division of Water, Forest, and Environment, CSIR, Pretoria, having been sourced from the CSIR’s Satellite Application Centre (SAC) data archives, South Africa. We thank Mark Thompson (Geospace International, Pretoria, South Africa) for his assistance in preparing this map and its interpretation. We thank the following artists for allowing us to use their illustrations—first published in Flora zambesiaca and Flora of Tropical East Africa—free of charge: Auriol Batten, Maureen Church, Derek Erasmus, Victoria Friis (Goaman), John Manning, Julia Loken, Mary Grierson, Christine Grey-Wilson, Eleanor Cather-

Rainbow on Nyika. xiv Plants of the Nyika Plateau

ine, Margaret Tebbs, Pat Halliday, and Heather Wood. Graham Williamson gave us permission to use his illustrations of orchid genera, many drawn from specimens he collected on the Nyika Plateau. We also thank personnel from Malawi’s National Herbarium (MAL), Zambia’s University of Zambia Herbarium (UZL), Mozambique’s herbarium (LMA) attached to the National Institute of Agronomic Research, Zimbabwe’s National Herbarium (SRGH), South Africa’s National Herbarium (PRE), and Compton Herbarium (NBG) for their determinations of the Expedition specimens and for sharing duplicate specimens with other herbaria within southern Africa. Antoinette Burkhardt prepared the maps of the Nyika National Park. We thank Elmar Robbrecht and Jan Rammeloo (BR) for their support in accessing Nyika-related information (specimens, photographs, and species lists) from the herbarium attached to the National Botanic Garden, Brussels, Belgium. In order to study Nyika specimens housed in herbaria in the U.K., C.K. Willis was supported through a SABONET internship for a study visit to the BM, K, FHO, and OXF herbaria in May 2003. Many researchers at these institutions offered assistance and useful discussions concerning the plants and botanical collectors of the Nyika Plateau: Richard Bateman and Roy Vickery (BM), Simon Owens, Dick Brummitt, Kate Pickard, James Kay, Brian Schrire, David Goyder, Gerald Pope, Henk Beentje, Kaj Vollesen, Alan Paton (K), Hugh Synge, Peter Overton, Stephen Harris, Alison Strugnell (FHO), and Serena Marner (OXF).

Introduction Where essential silence cheers and blesses, And forever in the hill-recesses Her more lovely music Broods and dies. O to dream, O to awake and wander There, and with delight to take and render, Through the trance of silence, Quiet breath; Lo! for there, among the flowers and grasses, Only the mightier movement sounds and passes; Only winds and rivers, Life and Death. —R.L. Stevenson

The Nyika Plateau—the largest montane complex in southcentral Africa—lies close to the northern tip of Lake Malawi. Most of the Plateau lies in Malawi, with a small section across the border in Zambia. The name “Nyika” means wilderness, and the Plateau consists of rolling grasslands, criss-crossed by deep valleys, with occasional forest patches.

Plants of the Nyika Plateau 1

Burchell’s zebra

T

he Nyika Plateau separates two of the major faults of the African Rift Valley system—Lake Malawi to the east and the Luangwa Valley of Zambia to the west. Nyika’s position along the Rift Valley system results in frequent earth tremors, and northern Malawi is, indeed, the most seismically active part of the country (Johnson 1993).

Acacia abyssinica

The Nyika Plateau occupies an area of some 1,800 km2 above the 1,800 m contour, which usually marks the zone of transition from woodland to montane grassland and forest. Of the total area, only about 70 km2 on the western side is within Zambia (Dowsett-Lemaire 1985). The Plateau, roughly oval in shape and oriented in a northeasterly direction, lies between 10O15’–10O50’S and 33O35’–34O05’E. Only the wet eastern escarpment is extensively forested. Between 2,100 m and 2,500 m, the central plateau (approximately 60% of the montane area) consists of rolling Loudetia—Andropogon grassland, interspersed with small patches of low forest. These forest patches account for less than three percent of the area (Dowsett-Lemaire 1985). The surface of the Plateau is gently undulating, with convex valley sides sloping at 10O to 15O. Towards the margins though, slopes are steeper, particularly in the north and east (Meadows 1984a). At times, the valleys that cut into the surface are up to 1 km wide, and 200 m deep. Usually, such valleys are partially filled with a variety of sediments (the maximum recorded depth being 6.2 m) (Meadows 1984a) and have poorly drained marshy floors. Occasionally, large high granite or resistant quartzite outcrops rise above the grassland. Most of the remote Nyika Plateau is included within Malawi’s Nyika National Park; originally called Malawi National Park, the name of the park was changed to the Nyika National Park in 1969. It is the largest of Malawi’s national parks and is currently administrated by the Department of National Parks and Wildlife. In 1978 the Nyika National Park area was extended from the initial 940 km2 to its current size and includes all of the plateau escarpments and most of the northeast and south hill zones (Johnson 1993). The park now spans 3,134 km2, with another 70 km2 on the western edge of the Nyika Plateau belonging to the Zambian Nyika National Park. The highest points on the Nyika Plateau are Nganda Hill at 2,607 m in the north, and Kasaramba at 2,460 m in the southeast. The lowest point drops to 580 m in the northeast corner of the park along the Ruwile River (Johnson 1993). Lake Kaulime near Chelinda is the only natural lake in the park–it was formed by a landslide that blocked the outflow from one of the headwaters of the North Rukuru River (Johnson 1993).

Climate

Nthakati Peak 2 Plants of the Nyika Plateau

Malawi has a single rainy season during the summer months of November to April (Dowsett-Lemaire 1985). Minimum monthly temperatures at Chelinda (2,300 m), Nyika National Park, vary between 11OC (June–July) and 16OC (November–December) (Dowsett-Lemaire 1985). A record minimum temperature of -12OC has been measured at Chelinda (G. Brown, pers. comm.). Maximum temperatures are relatively stable throughout the year and vary between 17OC and 20OC. Temperatures of up to 26 OC are recorded during September–November and February.

Nganda Peak

The high-rainfall areas (with an annual mean above 1,500 mm) are located on the eastern and western sides of the Nyika Plateau. Much of the high plateau above 2,200 m experiences a lower rainfall, usually averaging 1,000–1,200 mm per annum. The figures are even lower in the north, in the shadow of the high peaks of Nganda and Domwe (DowsettLemaire 1985). According to Cater (1993), most of the rain comes from the west, even though the prevailing wind throughout the year is easterly. Mist-belt conditions (known locally as chiperone) do not occur frequently in summer, but from June to September the eastern half of the plateau is often covered with cloud down to ground level (Cater 1993).

Drainage and soils There are four major rivers that have their source in the headwater dambos of the Nyika Plateau—the North Rukuru, North Rumphi, ChelindaRumphi, and the Runyina, all draining into Lake Malawi. These rivers are of great importance to water management in the Northern Region of Malawi, as water supply to much of this area would be totally cut off should the dambos ever dry up (Meadows 1984a). Spectacular rapids and waterfalls, such as the Chisanga Falls, are formed where rivers cut through the rim of the Plateau.

Roan antelope

The soils of the plateau are mainly acidic with a pH ranging from 4.0 to 5.5 (Williamson 1979). These humic latosols are typical of the highplateau soils of the tropics (Meadows 1984a).

Landslips There are many landslip scars on the Nyika Plateau, some relatively fresh and others older and revegetated. While earth tremors can be responsible for mass movement on a large scale and are known to occur on the Nyika Plateau, heavy rainfall is probably the main cause (Meadows 1984a). The landslips are concentrated in the eastern part of the plateau, a fact that suggests greater precipitation (or perhaps greater precipitation intensities) and consequently greater chemical weathering (Meadows 1984a). Geology may also affect landslip distribution, as Cordierite Gneiss is restricted to the eastern plateau (Thatcher 1974, Meadows 1984a). Some of these landslips are large, like the Chelinda 1960 event, but many are small and typically characterised by a pronounced concavity in the hillside and a hummocky topography lower down (Meadows 1984a). According to Meadows (1984a), landslips seem to be important in determining the vegetation pattern on the Nyika Plateau. Many of the forest patches are associated with the valley heads on the steeper slopes of the concavities, of which many are former landslip scars. Three factors favour the survival of the forest species in these scars: • In the initial post-movement period, much open ground is made available for the establishment of tree species since the broken topography and bare soil act as a firebreak. • The steeper slopes on which these forests are concentrated are not favourable to fire spreading, since fires tend to travel up, rather than down, steep inclines. Fire is unlikely to travel up these slopes from lower down, because the dambos, which consistently lie below the forests, are saturated even in the dry season and could therefore not be the source of fires.

Chisanga Falls Plants of the Nyika Plateau 3

Vitumbi Road • The soils that ultimately develop under the forest vegetation are deep and are a much better medium for plant growth, with greater moisture capacities that discourage fire (Meadows 1984a).

Fire Fire, nevertheless, plays an important role on the Plateau. Each hectare of plateau grassland is burned approximately every three years as stipulated by National Park policy. Management goes to considerable lengths to ensure that these fires do not destroy the forest patches and an elaborate system of fire-breaks has been constructed around the larger patches (Meadows 1984a). Lemon (1968) could find no evidence that the induced Nyika fires cause destruction of valuable forage plants and invasion by weeds, although there is a drain on the nutrient reserves. Indeed, the welfare of many species, particularly some legumes, such as Aeschynomene oligophylla, may well depend on periodic burning (Meadows 1984a). Plateau grassland is burned for two reasons. Firstly, controlled burns and fire-breaks initiated in the early part of the dry season ensure that the damaging hot burns later during the dry season do not happen. Secondly, burning appears to encourage game animals. Herds of bushbuck, zebra, eland, and roan antelope selectively graze the more recently-burnt ground, presumably because the fresh shoots that emerge after burning are more nutritious (Meadows 1984a).

Vegetation communities Within the Nyika National Park, miombo woodland covers roughly 60% of the park, montane grasslands and dambos around 37%, and evergreen forest more or less 3% (Johnson 1993). Four main vegetation communities are recognised and are described in more detail below.

Table 1. Breakdown of plant taxa on the Nyika Plateau. Families Genera Species

Infraspecific

Exotic species

taxa Pteridophytes

22

47

107

2

0

Gymnosperms

3

4

4

0

1

Monocotyledons

24

147

548

10

2

Dicotyledons

111

486

1,158

36

23

Totals

160

684

1,817

48

26

4 Plants of the Nyika Plateau

Table 2. The 21 largest genera on the Nyika Plateau. Genus

Family

Habenaria

Orchidaceae

Species 43

Vernonia

Asteraceae

31

Plectranthus

Lamiaceae

26

Crotalaria

Fabaceae

25

Disa

Orchidaceae

22

Helichrysum

Asteraceae

21

Indigofera

Fabaceae

21

Satyrium

Orchidaceae

20

Eulophia

Orchidaceae

18

Eragrostis

Poaceae

16

Panicum

Poaceae

16

Aeschynomene

Fabaceae

15

Hyparrhenia

Poaceae

14

Eriosema

Fabaceae

14

Cyperus

Cyperaceae

14

Scleria

Cyperaceae

14

Buchnera

Scrophulariaceae

13

Sporobolus

Poaceae

12

Bidens

Asteraceae

11

Rhynchosia

Fabaceae

11

Polygala

Polygalaceae

11

Table 3. A comparison between the largest families on the Nyika Plateau and Mt. Mulanje,* Malawi. Nyika Plateau (total taxa: 1,891) Orchidaceae

No. of species 200

Mt. Mulanje (total taxa: 1,317) Orchidaceae

No. of species 122

Asteraceae

185

Asteraceae

99

Poaceae

165

Poaceae

90

Fabaceae (sensu stricto)

159

Fabaceae (sensu stricto)

82

Rubiaceae

90

Rubiaceae

82

Cyperaceae

73

Euphorbiaceae

46

Lamiaceae

65

Cyperaceae

37

Euphorbiaceae

41

Lamiaceae

35

Apocynaceae (sensu lato)

41

Acanthaceae

31

Acanthaceae

33

Scrophulariaceae

20

Scrophulariaceae

33

* A. Strugnell, pers. comm. (2003).

Table 4. A summary of the 33 Nyika endemics. Taxon

Life form

Habitat niche

Notes

Suffrutex herb

Habitat unknown

Only three collections.

Peucedanum articulatum C.C.Townsend

Perennial herb

Wet montane grassland

Occasional.

Peucedanum sp. nov.,

Perennial herb

Montane grassland in wet areas

Occasional.

Geophytic herb

Streamsides in montane grassland

Occasional.

Suffrutex herb

Shallow soil over rock

Only one collection.

Suffrutex herb

Montane grassaland

From six collections.

Perennial herb

Montane grassland or woodland

Only Nyika-Malawi, from two

Acanthaceae Monechma varians C.B.Clarke Apiaceae

aff. P. harmsianum H.Wolff Pimpinella nyassica Norman Apocynaceae Ceropegia sp. [Goyder, Paton & Tawakali 3579 herbarium?] Glossostelma nyikense Goyder Asteraceae Brachythrix malawiensis (Wild & G.V.Pope) G.V.Pope

localities.

Brachythrix pawekiae Wild & G.V.Pope

Perennial herb

Montane grassland

Few collections only.

Brachythrix sonchiodes Wild & G.V.Pope

Perennial herb

Secondary forest or marshes/

Also Nyika-Zambia. Possibly

streamsides

widespread.

Helichrysum hilliardiae Wild

Perennial herb

Swamps or marshes in montane

Unspecified locality on Nyika

grassland

Zambia. Several collections on Nyika-Malawi. Locally common.

Miombo woodland

Only Nyika-Malawi. Locally

Helichrysum tithoniodes Wild

Perennial herb

common. Osteospermum nyikensis Wild

Perennial herb

Montane grassland

Two records only.

Vernonia fractiflexa Wild

Perennial herb

Montane grassland

Type locality only (near

Vernonia kawoziensis F.G.Davies

Perennial herb

Miombo woodland

Type locality only

Nganda Peak). (Kawozya Hill). Balsaminaceae Impatiens rubromaculata Warb. subsp.

Perennial herb

Moist forest

Taxonomy uncertain.

Succulent shrub

Bare rock

Only three collections.

Perennial shrub

Montane grassland at forest margins

Mainly eastern Nyika-Malawi. Perhaps only two collections. Rare.

Suffrutex shrub

Montane grassland

Nyika-Malawi only. Rare.

Kotschya africana Endl. var. latifoliola Verdc.

Perennial shrub

Rocky slopes & seepage areas

Occasional. Nyika-Zambia only.

Crotalaria pilosiflora Baker

Perennial herb

Miombo woodland

Probably widely distributed. Rare.

Suffrutex herb

Montane grassland

A number of collections.

schulziana (Launert) Grey-Wilson Crassulaceae Crassula nyikensis Baker f. Euphorbicaeae Phyllanthus nyikae Radcl.-Sm.

Fabaceae Indigofera hilaris Eckl. & Zeyh. var. microscypha (Baker) Gillett fringing evergreen forests

Lamiaceae Plectranthus acaulis Brummitt & Seyani

Frequent. Plectranthus zebrarum Brummitt & Seyani

Suffrutex herb

Montane grassland

A number of collections. Frequent.

Lobeliaceae Cyphia nyikensis Thulin

Herb (?)

Shallow soil over rock

Only one collection.

Geophytic herb

Wet & marshy grassland

Few collections only (possibly

Orchidaceae Cynorkis anacamptoides Kraenzl. var. ecalcarata P.J.Cribb

two).

Plants of the Nyika Plateau 5

Table 4. A summary of the 33 Nyika endemics. (cont.) Taxon

Life form

Habitat niche

Notes

Disa praecox (H.P.Linder) H.P.Linder

Geophytic herb

Montane grassland

A number of collections.

Disperis bifida P.J.Cribb

Geophytic herb

Forest floors

Limited distribution. Nyika-

Disperis breviloba Verdc.

Geophytic herb

Miombo woodland & montane

Habenaria livingstoniana la Croix & P.J.Cribb

Geophytic herb

Miombo woodland

Type locality only. Eastern

Habenaria riparia Renz & Grosvenor

Geophytic herb

Swampy areas & streamsides

Type locality only. Frequent.

Stolzia compacta P.J.Cribb subsp. compacta

Epiphytic herb

Montane forest

Single collection. Locally

(= Herschelianthe praecox )

Occasional. Zambia only. grassland escarpment. Rare.

common. Oxalidaceae Oxalis chapmaniae Exell

Geophytic herb

Montane grassland

Frequent.

Perennial herb

Drainage lines & forest margins

Frequent.

Perennial shrub

Montane scrub

Occasional.

Poaceae Setaria grandis Stapf Polygalaceae Polygala lactiflora Paiva & Brummitt

Table 5. A summary of the 13 near-endemics of the Nyika Plateau. (A near-endemic is defined here as a species occurring mainly on the Nyika but also found on the Viphya Plateau, Makutu Mountains, Mafinga Mountains and/or the Misuku Hills.) Acanthaceae Isoglossa strigulosa C.B.Clarke Euphorbiaceae Erythrococca trichogyne (Müll.Arg.) Prain var. psilogyne Radcl.-Sm. Euphorbia ampliphylla Pax Fabaceae Aeschynomene tenuirama Baker var. hebecarpa Verdc. Vigna phoenix Brummitt Lamiaceae

Chelinda Bridge

Ocimum obovatum E.Mey. ex Benth. subsp. crystallinum (A.J.Paton) A.J.Paton Orchidaceae Habenaria nyikensis G.Will. Habenaria petraea Renz & Grosvenor Habenaria pubidens P.J.Cribb Polygalaceae Polygala nyikense Exell Scrophulariaceae Buchnera crassifolia Engl. Buchnera nitida Skan Selaginaceae Selago thyrsoidea Baker var. thyrsoidea

Lake Kaulime 6 Plants of the Nyika Plateau

View looking south-westwards towards Mwanda Mountain forming the western edge of the Nyika Plateau.

Table 6. Comparison of the floristic richness and endemism of similar upland areas within the Afromontane archipelago. Area (km2)

Nyika Plateau, Malawi 3,204

Taxa/km2

Mount Mulanje, Chimanimani Mts, Malawi1 Zimbabwe2 640 390

Simien Highlands, Ethiopia3 ?

Mt Cameroon, Cameroon4 2,700

0.59

2.03

2.2

?

0.9

Number of total taxa

1,8915 (1,7826)

1,3035,6

859

550

2,4355 (2,2486)

Number of endemics

33

69

707 (418)

12

49

1.7%

5.3%

6

8.1% (4.8%)

2.2%

2.0%

13

25

?

?

?

Percentage endemism Number of near-endemics References:

Notes:

1. Strugnell (2002)

5. Includes subspecific taxa and naturalised exotic species.

2. Wild (1964), Mapaura (2002)

6. Excludes pteridophytes.

3. Puff & Nemomissa (2001)

7. After Mapaura (2002).

4. Cable & Cheek (1998)

8. After Wild (1964).

Gently undulating landscape of grasslands and forests on the Nyika Plateau.

Dambo feeding into the Dembo River, a tributary of the North Rumphi River.

Lobelia mildbraedii (Lobeliaceae) growing on the edge of Lake Kaulime, Nyika National Park. Plants of the Nyika Plateau 7