Cape plants : corrections and additions to the flora . 1

Comprising an area of ± 90 000 km:, less than 5% of the land surface of the southern African subcontinent, the Cape Floristic Region (CFR) is one of the world’s richest areas for plant species diversity. A recent synoptic flora for the Region has established a new base line for an accurate assessment of the flora. Here we document corrections and additions to the flora at family, genus and species ranks. As treated in Cape plants , which was completed in 1999. the flora comprised 173 families (five endemic), 988 genera (160 endemic: 16.2%), and 9 004 species (6 192 endemic: 68.8%). Just four years later, a revised count resulting from changes in the circumscriptions of families and genera, and the discovery of new species or range extensions of species, yields an estimate of 172 families (four endemic), 992 genera (162 endemic: 16.3%) and 9 086 species (6 226: 68.5% endemic). Of these, 948 genera and 8 971 species are seed plants. The number of species packed into so small an area is remarkable for the temperate zone and compares favourably with species richness for areas of compa­rable size in the wet tropics. The degree of endemism is also remarkable for a continental area. An unusual family compo­sition includes, in descending order of size, based on species number. Asteraceae. Fabaceae. Iridaceae. Ericaceae. Aizoaceae, Scrophulariaceae. Proteaceae. Restionaceae, Rutaceae. and Orchidaceae. Disproportionate radiation has resulted in 59.1% of the species falling in the 10 largest families and 74.6% in the largest 20 families. Thirteen genera have more than 100 species and the 20 largest genera contribute some 31.5% of the total species number.


INTRODUCTION
Published in September 2000, Cape plants (Goldblatt & Manning 2000) is a synoptic account of the vascular plant flora of the Cape Floristic Region (CFR) of southern Africa.As with such endeavours, it contained its share of errors and omissions.Moreover, changes to the systematics of plant taxa of the Cape flora have accumulated at a steady pace.Thus, despite our best efforts to produce an accurate and lasting account, we find after just four years since publication, and about five years since completed copy was handed to the publisher, that a fair number of corrections and additions are necessary.Most of these con cern species: 9 004 species were recognized in 2000.and we now include 9 086 species in the flora region.Some 988 genera were recognized in the flora in 2000, but with additions and taxonomic changes there are now 992 genera.We hope to continue to publish lists of additions periodi cally when such compilations seem useful.Changes to the account are discussed in detail below under the headings Families, Genera, and Species.
Families.Changes in familial classification, resulting from the continuing molecular research in angiosperm phylogeny, have compelled adjustments to the generic constitution of several families [Angiosperm Phylogeny Group (APG) 1998, 2002).The rule of priority has also made necessary some name changes.Most notable for the CFR is the work of Olmstead and his collaborators in the Lamiales-Scrophulariales which has shown that Veronica L. and its allies, previously Scrophulariaceae, should be included in an expanded Plantaginaceae (Olmstead et al. 2001).In the Cape flora the genera affected include Limosella L. (two spp.) and llysanthes Raf.(one sp.), which are accordingly transferred to Plantaginaceae.These studies also show that several African genera of Scrophulariaceae and Loganiaceae comprise a clade with the Cape family Stilbaceae.In order to retain monophyletic family circumscriptions, these genera have been trans ferred to Stilbaceae (alternatively Stilbaceae and several more families would have to be included in Scro phulariaceae).Thus Halleria L. (three spp.) and Ixianthes Benth.(one sp.) are removed to Stilbaceae, which ceases to be endemic to the CFR.Nuxia Comm, ex Lam.(pre viously Loganiaceae) also belongs in an expanded Stilbaceae while Buddleja L.. previously Loganiaceae and more recently Buddlejaceae.is now included in Scro phulariaceae.This leaves Scrophulariaceae with 31 genera and 409 species, and Loganiaceae with one genus (Strychnos L.) and two species in the CFR.
Another important familial change is the union of the endemic southern African family Achariaceae with Kiggelariaceae (Savolainen et al. 2000).The conserved name Achariaceae is used for the expanded family.The endemic Cape tree Hyaenanche Lamb.& Vahl (one sp.) is now known to be nested in Picrodendraceae (= Pseudanthaceae) (Savolainen et al. 2000) and is transferred to this family from Euphorbiaceae.The status of the monotypic Curtisia Aiton, usually included in Comaceae, has varied with time.Molecular data show that the genus is sister to the Cape endemic family, Grubbiaceae, and recognition of a monogeneric Curtisiaceae is recommend ed by APG (2003).The family Comaceae is thus no longer represented in the Cape flora.In the monocots, the South African and near Cape endemic.Prioniaceae (with the monotypic Prionium E.Mey.) is sister to the South American Thumia Hook.f. and has been referred to Thumiaceae by Chase et al. (2000).Tamaricaceae.repre sented by one species of Tamarix L. in the Cape flora, was omitted in enror from Cape plants.
Convallariaceae. the family that includes Dracaena L.( Eriospermum Jacq.ex Willd.and Sansevieria Thunb., must now be known by the earlier name, Ruscaceae.The APG (2003) recommend that Ruscaceae as well as Anthericaceae and Hyacinthaceae be included in an enlarged monophyletic Asparagaceae.They also favour union of Agapanthaceae and Amaryllidaceae in Alliaceae and Asphodelaceae and Hemerocallidaceae in Xanthorrhoeaceae.Alternative treatment is permitted and for the present we do not follow these recommendations and maintain the narrower family circumscriptions in Cape plants.
Another family realignment is the inclusion of Centella L. in Apiaceae (Araliaceae in Cape plants) as a result of extensive molecular study (Lowry et al. 2004) At family level it is most notable that the flora loses its second largest endemic family, Stilbaceae, which in its expanded circumscription extends through tropical Africa and Madagascar to Arabia (Halleria, Nuxia).This leaves only four endemic families in the CFR: Penae aceae in Myrtales (21 species), Grubbiaceae in Comales (three species).Roridulaceae in Ericales (two species), and Geissolomataceae in Saxifragales (one species) (classification follow ing APG 2003).Based on a molec ular clock calibrated using 135 mya for the divergence of the eudicot lineage (Savolainen et al. 2000;Wikstrom et al. 2001;V. Savolainen unpubl. ms), Penaeaceae may have diverged 20 mya from its sister clade, the African Oliniaceae plus the Neotropical Alzateaceae, whereas Roridulaceae diverged from Ericaceae, its closest relative (Savolainen et al. 2000), ± 48 mya.Geissolomataceae appears to be older, having diverged perhaps 55 mya from Ixerbaceae plus Strasburgeraceae.Grubbiaceae may have diverged from Curtisiaceae in the early Tertiary, 63 mya.
Bruniaceae, one of the distinctive families of the Cape flora, has an estimated 64 species in 11 genera (Goldblatt & Manning 2000).Just three species in two genera extend outside the confines of the Cape Region, two locally, and one as far east as southern KwaZulu-Natal.Bruniaceae may be the sister group to the order Dipsacales (Savolainen et al. 2000), perhaps meriting recognition at ordinal rank.The discovery of pollen matching modem Bruniaceae in early Tertiary and late Cretaceous (?Senonian) deposits in northern Namaqualand (S.E.de Villiers pers.comm.), well to the north of the CFR, attests to considerable age for the family in southern Africa.The pollen record also accords with a preliminary early Tertiary dating of the divergence between Bruniaceae and Dipsacales at about 57 mya (V.Savolainen unpubl.ms.).In the later APG (2003) classi fication, however, Brunicaeae are not assigned to any order in the Euasterids II group.
With the above changes, there are now 149 families of seed plants, and 23 families of ferns and other vascular cryptogams, for a total of 172 families of vascular plants in the CFR.This is one less than was recognized in Cape plants.Anticipated transfer of two genera of Portulacaceae to Didieriaceae would bring the total num ber of seed plant families to 150.The CFR is character ized by an unusual family composition that includes, in descending order of size (species number) following Asteraceae and Fabaceae, the families Iridaceae, Eri caceae, Aizoaceae, Scrophulariaceae, Proteaceae, Restionaceae, Rutaceae, and Orchidaceae, among the 10 most species-rich families in the flora.Asteraceae alone, with 1 048 species, contributes 11.5% of the total species in the flora.Disproportionate radiation in the 20 largest families (Table 1) has resulted in over 59% of the species falling in the 10 largest families and more than 74% in the largest 20 families.Genera.A total of 942 genera of seed plants (or 988 genera of vascular plants) were included in the Cape flora by Goldblatt & Manning (2000), comprising about half of all those occurring in southern Africa.Of those, some 160 genera (all of them seed plants), were endem ic, constituting 16.2% of the total vascular plant flora.The inclusion of Tamaricaceae in the flora adds one more genus, Tamarix, and the recent discovery of a species of Clivia Lindl.(Amaryllidaceae) in the Cape flora (Rourke 2002) is a second generic addition.The genus Pilularia L. (Marsileaceae) has also recently been recorded for the first time in the flora (Roux 2(X)2).Carpolyza Salisb.(Amaryllidaceae) has been found by molecular analysis to be nested in Strumaria Jacq.ex Willd.. in which it is now' included (Meerow' & Snijman 2001).Also in Amaryllidaceae, the monotypic Cxbistetes Milne-Redh.& Schweick.is now included in Ammocharis Herb.(Snijman & Archer 2(X)3).In Aizoaceae, some species previously assigned to Lampranthus N.E.Br.and Ruschia Schwantes are now referred to the new endemic genera Brianhuntleya Chesselet, S.A. Hammer & I.Oliver (monotypic) (Chesselet et al. 2003), and Phiambolia Klak (7 species) (Klak 2003).
Old herbarium records, until now overlooked, show that Calystegia R.Br.(Convolvulaceae) and Chaetacme Planch.(Celtidaceae) occur naturally in the Cape flora, adding another two genera to the total.Another generic omission is Gomphostigma Turcz., now added to Scro phulariaceae.In Asteraceae, a new monospecific genus Roodebergia B.Nord. has been described (Nordenstam 2002b) and two species of Dicoma Cass, have been transferred to Macledium Cass., thus adding two more genera to the flora.The endemic genus Alciope DC. (Asteraceae), has been found to be nomenclaturally ille gitimate, and is now called Capelio B.Nord.(Nordenstam 2002a(Nordenstam , 2003a)).Lastly, in Hyacinthaceae the endemic species Scilla plumbea has been shown by molecular data to be misplaced generically and has been assigned to the new and endemic genus Spetaea Wetschnig & Pfosser, as S. lachenaliiflora Wetschnig & Pfosser (2003).Also in Hyacinthaceae, Albuca L" Dipcadi Medik.and Neopatersonia Schonland have been sunk in Ornithogalum L., Whiteheadia Harv. in Massonia Thunb.ex Houtt., and Polyxena Kunth is included in Lachenalia J.Jacq.ex Murray (Manning et al. 2004).This reduces the number of genera but signifi cantly enlarges Ornithogalum.which now has 72 species (previously 40 species) in the Cape flora, while Lachenalia now has 69 species in the flora.
Recent molecular studies on Zygophylloideae (Beier et al. 2003) have resulted in substantial restructuring of the genera in the subfamily.Zygophyllum L. is now understood to be restricted to Asia and the majority of the southern African species of Zygophyllum have been referred to the genus Roepera A.Juss.The species of Zygophyllum subg.Agrophyllum Endl.are placed in the genus Tetraena.
With these changes there are currently 948 genera of seed plants, or 992 genera of vascular plants recognized in the CFR.This is an increase of four genera to the pre vious total for the flora (Goldblatt & Manning 2000).Of these, 162 genera (16.3%) are endemic, representing an insignificant increase in generic endemism over that recorded in Cape plants.Thirteen genera have more than KM) species and the 20 largest genera contribute some 2 858 species, or 31.5% of the total in the flora (Table 2).Species.The number of species added to the flora is considerable and we list changes below by family alpha betically.New inclusions are provided with treatments comparable to those in Cape plants, including brief descriptions, and notes on flowering time, distribution, habitat, and phytogeographic centre(s) within the Cape Region.Corrections to species names, descriptions, or ranges are included in the list that follows.The sign * indicates endemic to the CFR and the sign !indicates introduced species.With the additions and corrections, the Cape flora now includes 9 086 species of vascular plants, 6 226 endemic (8 971 species of seed plants, 6 217 endemic) with a percentage endemism of 68.5 %.This represents an increase of 80 species since the publi cation of Cape plants and a reduction in endemism from 68.8%.In Table 1 we list the ten largest families in the flora with their number of species and degree of endemism.
Six phytogeographical subcentres are recognized in the Cape Region and their abbreviations used here are: NW (Northwest Centre); SW (Southwest Centre); AP (Agulhas Plain); KM (Karoo Mountain Centre); LB (Langeberg Centre); and SE (Southeast Centre) (see front endpaper of Cape plants).
. Also likely as a result of sequence studies, is the removal of Ceraria H.Pearson & Stephens and Portulacaria Jacq.from Portulacaceae to Didieriaceae.This previously endemic family of Madagascar forms a sister clade with Portulacaceae s.s.(Applequist & Wallace 2001).The changes involving Portulacaceae have not yet been for malized in the literature (APG 2003), and are not taken into account here.