Swaziland ferns and fern allies Recommended citation format ROUX, J.P. 2003. Swaziland ferns and fern allies. Southern African Botanical Diversity Network Report No. 19. SABONET, Pretoria. Published by Southern African Botanical Diversity Network (SABONET), c/o National Botanical Institute, Private Bag X101, 0001 Pretoria. Tel.: +27 12 804-3200 Fax: +27 12 804-5979 E-mail: [email protected] from whom copies of reports in this series are available on request. Printed in 2003 in the Republic of South Africa by Capture Press, Pretoria, +27 12 349-1802. ISBN 1-919795-97-9 © 2003 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. The SABONET Project Coordinator (address above) would appreciate receiving a copy of any pub- lication that uses this report as a source. Copy editors: Cecilia de Vos Belgraver, Marthina Mössmer, and Lidia Gibson Cover: Cheilanthes eckloniana (Kunze) Mett. (Photo: J.P. Roux) Cover design: Antoinette Burkhardt, Pretoria, South Africa +27 82 909-0109. Text design and layout: Antoinette Burkhardt SABONET web site: http://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 Interna- tional Development (USAID)/World Conservation Union-Regional Office for southern Africa (IUCN ROSA) (Plot no. 14818 Lebatlane Road, Gaborone West, Extension 6 Gaborone, Bot- swana), 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 USAID, the GEF/UNDP, the SABONET Steering Committee or SABONET National Working Groups. Swaziland ferns and fern allies J.P. Roux Compton Herbarium National Botanical Institute Southern African Botanical Diversity Network Report No. 19 ❖ 2003 Contents Acknowledgements....................................................................................................................vi Introduction................................................................................................................................1 Topography..................................................................................................................................3 Geology........................................................................................................................................3 Climate........................................................................................................................................6 Vegetation ...................................................................................................................................7 Conservation...............................................................................................................................9 Taxonomy.................................................................................................................................. 11 Abbreviations and glossary....................................................................................................223 References...............................................................................................................................229 Index........................................................................................................................................233 Acknowledgements My appreciation goes to Prof. G.F. Smith and the SABONET Steering Committee for support- ing the project. Mr G.M. Dlamini, Titus Dlamini, and Christopher Tsabalala, staff of the Swaziland National Herbarium, are thanked for providing invaluable assistance whilst I visited the country, as well as the Swaziland National Trust Commission, which issued the necessary permits that allowed me to collect in the various national parks. I am grateful to Kate Braun for providing accommodation and sharing invaluable information. Les Powrie is thanked for helping with the preparation of the distribution maps, and Dr Cora Ovens for proofreading the text. Swaziland ferns and fern allies Introduction It is recorded that Ernest Galpin was the first cited by the flora that after his retirement in person to collect plants in Swaziland. Galpin, a 1953 as Director of the then National Botanic banker and plant enthusiast, was transferred Gardens of South Africa, he moved to Swaziland to Barberton in June 1889, where he lived un- and settled on the farm Ukutula outside til the end of 1892 before being transferred to Mbabane (Compton 1966). Two years later he Queenstown (Gunn & Codd 1981). During this was asked by the Swaziland government to start time he collected numerous plants from the a botanical survey of the country and was pro- surrounding mountains, which were sent to vided with a technical assistant, a four-wheel Kew, Harry Bolus at the Cape, Medley Wood at drive vehicle, and a small herbarium building. the Durban Botanical Garden, MacOwan at the Unfortunately, in 1966 his subsidy, transport South African Museum herbarium, and Zurich. and herbarium building were withdrawn and Further collections were made in 1890 by E. fieldwork was stopped. He was able to devote Saltmarshe, who visited the Bulembu area, or all his attention to this project and the prelimi- the Havelock Concession, as it was known at nary results of this task were published in 1966 the time. In 1906 Harry Bolus visited Mbabane as An annotated check-list of the flora of and collected at Dalriach outside Mbabane and Swaziland (Compton 1966). In this list, 73 also travelled to the middleveld. Miss Mabel pteridophyte species were recorded for the coun- Stewart was the first Swaziland resident who try. For an unknown reason the pteridophytes is known to have collected in that country, at were omitted from the Flora of Swaziland first around Mbabane and later at Hlatikhulu (Compton 1976). Today, this monumental work where she lived. Her specimens were sent to in which 2 118 species are described, still re- South African herbaria and many of them are mains the standard work for the flora of the housed in the South African Museum (SAM) country. Additions were published by Kemp in herbarium at the Compton Herbarium, 1981. More recently, A flora checklist for Kirstenbosch (Gunn & Codd 1981). Swaziland (Kemp 1983) was published, bring- ing the number of pteridophytes known for the The Englishman Joseph Burtt Davy arrived in country to 90 species. South Africa in 1903 and in March that year he took up a post as botanist and agrostologist in During 2001 I conducted a survey of pterido- the newly formed Transvaal Department of phyte specimens housed in some of the south- Agriculture, where he worked until his retire- ern African herbaria, and concluded that no ment in October 1913 (Gunn & Codd 1981). pteridophytes are known from large parts of the Burtt Davy was a keen botanist and published country. Several species occurring in neighbour- A first check-list of flowering plants and ferns ing South Africa have never been recorded for of the Transvaal and Swaziland in 1912 with Swaziland. As a consequence, an intense the assistance of Pott-Leendertz. This was the pteridophyte survey was carried out in the area first list in which plants from Swaziland were during the period 5 to 23 May 2002, during included. In 1919 Burtt Davy returned to Eng- which nearly 400 specimens were assembled. land and started working on The manual of The first set of this collection is housed in the flowering plants and ferns of the Transvaal with Compton Herbarium (NBG). The aim of the Swaziland, South Africa. Two parts if this pro- survey was to collect and record the distribu- posed four-part publication were published in tion of pteridophytes throughout Swaziland. 1926 and 1932, but Burtt Davy died and the During this period several species were recorded project was terminated (Gunn & Codd 1981). for the first time in the country bringing the These two parts list 217 plant species for number of species currently known for the re- Swaziland (Compton 1966), of which nine are gion to 112. The season during which the sur- pteridophytes. vey was carried out was unfortunately a very dry one and the lowveld and Lubombo region still re- Professor R.H. Compton visited Swaziland in main poorly known. It is expected that several 1947 with Dr. G.W. Reynolds and was so ex- more pteridophyte species will be added later. 1 Swaziland ferns and fern allies In this publication the family and generic se- pects are dealt with under the following head- quence follows Roux (2001), whilst the species ings (definitions for the terms are provided in are arranged alphabetically for convenience. In the glossary): the species descriptions the lower and higher size ranges recorded are bracketed, and statis- Habitat preferences tical means are given for stomata and spores. – Substrate preferences (terrestrial, epilithic, The statistical mode is given for the number of epiphyte, or chamaeophyte) indurated annulus, epistomium and hypo- – Soil and moisture conditions stomium cells per sporangium. Ecological as- – Light requirements e g n a R ndeza River So ati m o L 32ºE 26ºS 26ºS er v Ri ati s m Hill K o 31ºE a y n e w Ng River ns M buluzi untai o M o b m o b u L Lusutfu River 27ºS 27ºS 31ºE Ngwavuma River Figure 1. Map of Swaziland illustrating the topography with contours at 500 m intervals, perennial streams and rivers, and the major mountain ranges. 2 Swaziland ferns and fern allies Adaptive features the siSwati, with Lundzi at 1 540 m and Sicu- – Life forms (mega-, meso-, micro-, nusa at 1 100 m above sea-level. The highveld nanophanerophytes, hemicryptophytes, is the region lying above 1 000 m. geophytes or therophytes) – Structure of the photosynthetic organs The middleveld occupies the region between 400 (hygro-, meso-, xeromorphic), hydrostatics and 1 000 m above sea-level. In the western (poikilohydry) parts of the country it intrudes into the highveld – Vegetative reproduction in deep valleys. Although the transition between – Seasonal behaviour the highveld and middleveld is usually gradual, – Fire resistance the descents from the highveld may also be To indicate the distribution of species within abrupt, as from Mbabane to the Ezulweni val- Swaziland a two-system approach is followed. ley, and the descent into the Komati valley on Global Positioning System (GPS) readings are the road between Mbabane and Pigg’s Peak. generally not available for older collections and Although still hilly, the region is less undulat- since the exact locality cannot be plotted, the ing, with numerous smaller seasonal and per- quarter-degree square in which the plant was ennial streams originating in or flowing through collected is shaded. Where GPS readings are the region. Infrequent along these drainage available, the collecting locality is indicated by channels are small alluvial flats with seasonal a dot. For distributions outside Swaziland, but marshes. In contrast to the western middleveld, still within the African region, the level 3 re- where granite and gneiss are the predominant gional names of Brummit (2001) are followed. rock formations, the eastern Lubombo moun- Author citations follow the style of Brummitt tain range consists of lavas. The Lubombo re- & Powell (1992), journal abbreviations are given gion runs parallel to that of the western as in Botanico-Periodicum-Huntiarum/Supple- middleveld, but is less fragmented. However, ment (Bridson 1991), and abbreviations of book three gorges are formed where the Mbuluzi, titles follow Stafleu & Cowan (1976–1988). Lusutfu and Ngwavuma rivers cut through the Herbarium acronyms are based on Holmgren mountain range. The highest point in this re- et al. (1990). gion, Isateki, reaches 774 m above sea-level. Streams originating on the Lubombo range are Topography usually seasonal, which, north of the Lusutfu river, drain east and west. Swaziland occupies an area of 17 364 km2 (± 1 735 300 ha) and is located on the eastern The lowveld, or Ihlandze, is the region which rim of southern Africa, where it lies between lies below 400 m. This almost featureless re- the latitudes 25°43’ and 27°19’ S, and the gion is gently undulating with alluvial flats of- longitudes 30°47.5’ and 32°06’ E (Figure 1). It ten forming along the main river systems. The is situated along the eastern watershed of the region is currently used for intensive cattle and Drakensberg running north-south. Four major sugarcane farming, but a small area, the Hlane river systems, the Komati, Mbuluzi, Lusutfu Wild Life Sanctuary, has been set aside for con- and Ngwavuma rivers, drain the country. These servation. are all perennial rivers originating on the Mpumalanga highveld to the west of the coun- Geology try which form deep valleys as they cut through the mountainous terrain. Rock formations in Swaziland consists of many igneous and volcano-sedimentary types (Keyser The Sondeza, Makhonjwa and Ngwenya moun- 1997). These formations were laid down over tains along the northern and north-western an exceptionally long period, which can be di- border of the country form the highest region, vided into a series of Precambrian events which reaching 1 837 m at Ngwenya North. To the took place during the Swazian and Randian south, however, the terrain gradually becomes Erathems and a, geologically speaking, more less mountainous, but still forms part of the recent Postcambrian or Mesozoic event (Ta- highveld region, or Inkangala, as it is known to ble 1). 3 Swaziland ferns and fern allies The current Swaziland landscape is character- base on which other rock formations developed. ised by a large number of granite and gneiss These overlying formations have eroded and plutons. These formations extend over large weathered away, exposing the igneous types. areas and are the predominant rock types in the country. Granite and granitoid rocks are The approximately nine gneiss and granite igneous types and are therefore viewed as the plutons exposed today were formed during the Table 1. Stratigraphy of the major volcano-sedimentary and igneous rock formations in Swaziland. (Rock formation codes follow Keyser 1997, whilst the approximate ages are given in square brackets). Volcano-sedimentary rocks Igneous formations Jozini Formation Jj [± 200] Phanerozoic Karoo Sequence Lebombo Group P-Tr Letaba Formation Jl [± 205] Sandstone Trc Unidentified lava Dolerite dykes Jd Mswati Granite Suite Rmw [2 723] Biotite granite Kwetta Granite Rkw [2 780] Hlelo Granite Suite Usushwana Complex Ru [2 900] Randian Piet Retief Gobba Suite Nhlangano Granite Gneiss Rnh [2 822] Hlatikulu Granite Rhl [2 875] Mozaan Group Rmz [2 860] Pongola Sequence Nsuge Group Rns [2 984] Mpuluzi Granite Zmp [3 079] Quartz monzonite Unnamed gneiss Zmh [<3 100] Hornblende tonalitic gneiss Usuthu Suite Zus [3 100] Granodiorite, diorite, tonalite, quartz gabbro Moodies Group Zm Swazian Barberton Fig Tree Group Zf Sequence [± 3 500] Onverwacht Group Zo Mlika granodiorite Zml [± 3 150] Granodiorite Tsawela gneiss Zts [3 458] Hornblende- biotite tonolite gneiss Unidentified gneiss Zmg [3 553] Ngwane gneiss Zng [3 644] Tonalitic gneiss 4 Swaziland ferns and fern allies Swazian and Randian Erathems and span 921 western border of Swaziland. As a result of its m.y. The oldest is the Ngwane gneiss pluton, lithostratigraphy, the formation is subdivided with an age of 3 644 m.y. old, and the Mswati into three groups: the older Onverwacht Group, Granite Suite is the youngest at 2 723 m.y. old the Fig Tree Group, and the younger Moodies (Figure 2). Group. These rocks have been radiodated to be approximately 3 500 m.y. old (Kent 1980). Formations from the Swazian erathem, >3 100 m.y. old, also consist of volcano-sedimentary The Onverwacht Group consists of a thick suc- types. These rocks belong to the Barberton se- cession of mafic and ultramafic lavas overlain quence, also referred to as the Barberton by rhyolite (lava which banded as a result of its Greenstone belt and are found along the north- flow) deposited on an ancient oceanic environ- Figure 2. Map of Swaziland illustrating the major geological formations based on Keyser (1997). 5