Bothalia 29,1: 119-137 (1999) Montane flora of the southern Langeberg, South Africa: a checklist of the flowering plants and ferns D.J. MCDONALD' Keywords: checklist, flora, forest, fynbos. Langeberg, South Africa, Western Cape ABSTRACT The flora of the southern Langeberg is rich, w ith 1 228 species and intraspecific taxa (referred to collectively as species) recorded in 361 genera and 105 families. An analysis of the montane flora of the southern Langeberg. Western Cape, South Africa based on an annotated checklist shows that the Asteraceae has the highest number of species per familv (167) and the genus Erica has the most infrageneric taxa per genus (130) as well as the most endemic species (51). One endemic monotypic family, the Geissolomataceae, two endemic genera Geissoloma and Langebergia (Asteraceae) and a total of 167 endemic species are found on the southern Langeberg The plant families of the southern Langeberg flora are ranked accord­ ing to species-richness of the families and compared with floras of other areas (mainly montane) in the Fynbos Biome and marginally to the east of this biome (the Amatole Mountains). The greatest similarity of ranking is evident betw een the plant families of the southern Langeberg and those of the Cape Hangklip Area. INTRODUCTION found along the mountains of the eastern escarpment of southern Africa (Hilliard & Burtt 1987). Floras of the west-east-trending mountains of the Cape Fold Belt east of 19° S are not well documented. The flora of the southern Langeberg is analvsed and Lists of species exist for mountains where phytosocio­ compared with published lists of taxa found in the Cape logical studies have been carried out (Taylor 1979; Hangklip Area (Boucher 1977), Cape of Good Hope Taylor & Van der Meulen 1981; Bond 1981; De Lange Nature Reserve (referred to here as Cape Point) (Taylor 1992) but these have not been published. The flora of the 1985), Cederberg (Taylor 1996). Swartbos(ch)kloof southern Langeberg presented here originated as a (McDonald & Morley 1988), as well as the Zuurberg ‘working checklist’ of plant species recorded on the National Park (Van Wyk et al. 1988) and the Amatole southern Langeberg Mountain Range, during a survey of Mountains (Phi 11 ipson 1987). situated at the eastern edge the vegetation of three transects over the range of the Fynbos Biome. (McDonald 1993a, b, c). The first transect was situated "in the Boosmansbos Wilderness Area (BWA) the second in the Marloth Nature Reserve (MNR) and the third partly STUDY AREA in the Garcia State Forest and partly on state land at Witelsberg. These areas are well protected but apart from The southern Langeberg is delimited as the Langeberg a superficial, unpublished list of plant species for MNR Mountain range from Kogmanskloof at Montagu (33° 48' S. and a list of rare and endangered species found in the 20“ 10' E) in the west, to the Gouritz River near Mossel Langeberg East Mountain Catchment Area (Cape Nature Bay in the east (33° 57' S. 2 12 38' E). covering an area of Conservation, unpublished records), no comprehensive 174 857 ha. The lower limits of the mountain on the checklists of the flora of the southern Langeberg have south and north sides are taken as the boundaries been compiled. This compilation of the southern between the mountain catchments and adjacent agricul­ Langeberg flora is also a response to Siegfried’s (1989) tural land. urgent plea for the compilation of species lists, especially of plants, given the poor knowledge of the status of biota The Langeberg forms part of the west-east-trending in many of southern Africa’s nature reserves. Cape Fold Belt consisting mainly of quartzitic sandstone and shales of the Table Mountain Group. The steep An attempt has been made to make this checklist of south-facing (polar) cool, moist slopes rise above the the southern Langeberg flora as comprehensive as possible. Agulhas-Riversdale coastal plain (Cowling et al. 1988; It therefore contains records of montane fynbos and for­ Rebelo et al. 1991) and contrast sharply with the dry. est species, in the declared nature reserves mentioned north-facing (equatorial) slopes adjacent to the arid Little above as well as in other state- or privately-owned moun­ Karoo. The complex geology and steep climatic gradi­ tain catchments ol the southern Langeberg. The species ents. particularly from south to north, give rise to a wide recorded are essentially montane hut some of the species array ol habitats, w ith a high diversity of plant species. may also be found in adjacent lowland fynbos and forest Further details of physiography and climate are given in communities. Many of the species are Cape endemics, McDonald (1993a. b. c). whereas others are Afromontane linking species, being METHODS * Conservation Biology. National Botanical Institute Private Bag X7. 7735 Claremont, Cape Town The systematic checklist of the flora of the southern MS received: 1998-06-05. Langeberg represents a compilation from various sources 120 Bothalia 29,1 (1999) including unpublished information from a number of high-altitude wet slopes; MSS, mesic south slopes; 8) systematists currently working on the taxonomy of the Dispersal mode: A, ant; P, passive/unknown; VE, verte­ Cape flora. Initially, a ‘working list’ of species was com­ brate; W, wind; WA, water; 9)* Listed in the Red Data piled from 304 sample plots in the fynbos shrublands and List of southern African plants and subsequent updates forests of the southern Langeberg (McDonald 1993a, b, (Hilton-Taylor 1996a, b; 1997). c). Many species were identified only from poor speci­ mens collected from the sample plots. Those specimens The flora of the southern Langeberg was compared were not deposited in a herbarium as vouchers. All with those of six other floras in the Cape Floristic Region, voucher collections from the Langeberg taken during the Cape Hangklip (HKL), Cedcrberg (CED), Swartboskloof above-mentioned survey are housed in the Compton (SBK), Cape Point (CP), Zuurberg National Park (ZNP) Herbarium (NBG). Each taxon in the list was checked in and Amatole Mountains (AM) using an analysis of per­ the two principal Cape herbaria, Bolus Herbarium, centage similarity of the data in Table 3. The southern University of Cape Town (BOL) and Compton Herba­ Langeberg flora was ordered according to genera with ten rium, National Botanical Institute, Kirstenbosch (NBG). or more species, ranked in descending order of abundance Stellenbosch University Herbarium (STEU) was also and then analysed together with the other floras using the checked for Geraniaceae. To augment the ‘working list', unweighted pair-groups method using arithmetic aver­ the descriptive catalogue of the Cape flora compiled by ages (UPGMA) (Gauch 1982) with a percentage similar­ Bond & Goldblatt (1984) was consulted. The distribution ity coefficient (Kovach 1998). range of each species in the catalogue was noted and if a species was found to occur in the Swellendam, Heidelberg or Riversdale Districts it was included in the RESULTS list. Each of these records was then checked to determine whether the species was montane or found only on the The southern Langeberg has a rich flora with a total of coastal foreland. Only montane species were included in 1 228 species and infraspecific taxa (referred to collec­ the final list. The checklist was further augmented by tively as species) found in a total of 105 families and 361 including forest species recorded in the Boosmansbos genera (Table 1). There are relatively few pteridophytes and Grootvadersbosch forests by Geldenhuys (1992). A and gymnosperms and at the generic, specific and infra- number of undescribed species, mainly in the genera specific levels, monocotyledons number less than hall Erica (E.G.H. Oliver pers. comm.) and Psoralea (C.H. the number of dicotyledons. Similar to other South Stirton pers. comm.), were also included for the sake of African floras, the Asteraceae has the highest number of completeness. species, whereas the species:genus ratio (S/G ratio) is low (3.5), indicating a spread of species over a large Where listed species were collected by me, those col­ number of genera (Table 2) (Gibbs Russell 1985). In con­ lections have been used as vouchers to represent the trast, the Ericaceae has a high S/G ratio (18.6) since it species. Where I did not collect a given species, other has many species concentrated in a few genera, notably specimens of those species collected from the southern Erica which has the greatest number of species per genus Langeberg (mostly housed in NBG) were selected as (130) of any genus recorded in the area, as well as the vouchers to represent the remaining species where possi­ most endemic species (51) (Table 2). In the flora as a ble. Representative vouchers of species not represented whole, the Geraniaceae has the highest S/G ratio since it in NBG were selected from specimens in the Bolus is represented by only one genus. Pelargonium with 24 (BOL) and South African Museum (SAM) herbaria. species (Tables 2 & 3). The flora has a 13.2% level of en­ Alien species were not included in the list. demism with 167 endemic species (McDonald & Cowling 1995) with two endemic genera Geissoloma The checklist is systematically arranged according to (Geissolomataceae) and Langebergia (Asteraceae) (Nor- the numbering of genera by De Dalla Torre & Harms denstam 1996) and a single endemic monotypic family, (1958) in accordance with the Engler system, following the Geissolomataceae (Dahlgren & Rao 1969). Of the Arnold & De Wet (1993) but incorporating some more 1 228 species recorded. 111 of these are listed in the Red recent taxonomic changes e.g. the recognition of families Data List of southern African plants (Hilton-Taylor such as Lanariaceae. Anthericaceae and Agapanthaceae. 1996a, b; 1997) and reference should be made to these Each species recorded is followed by a sequence of codes publications for the status of each of these species.