Bothalia Volume 30

132 Pages·2000·11 MB·English

Bothalia
A JOURNAL OF BOTANICAL RESEARCH
Vol. 30,1 May 2000
TECHNICALPUBLICATIONS OFTHE NATIONALBOTANICALINSTITUTE,
PRETORIA
Obtainable from the National Botanical Institute, Private Bag X101, Pretoria 0001, Republic of
SouthAfrica.Acatalogue ofall available publications will be issued on request.
BOTHALIA
Bothalia is named in honourofGeneral Louis Botha, first Premierand MinisterofAgriculture of
the Union of South Africa. This house journal of the National Botanical Institute, Pretoria, is
devoted to the furtherance ofbotanical science. The main fields covered are taxonomy, ecology,
anatomy andcytology. Two parts ofthejournal and an index to contents, authors and subjects are
published annually.
Two booklets ofthe contents (a) toVols 1-20and (b) toVols 21-25, areavailable.
STRELITZIA
Aseriesofoccasional publicationson southernAfrican floraandvegetation, replacingMemoirsof
the BotanicalSurvey ofSouthAfrica andAnnalsofKirstenbosch Botanic Gardens.
MEMOIRS OFTHE BOTANICALSURVEYOFSOUTHAFRICA
The memoirs are individual treatises usually ofan ecological nature, but sometimes dealing with
taxonomyoreconomicbotany.Published: Nos 1-63 (manyoutofprint).DiscontinuedafterNo. 63.
ANNALS OFKIRSTENBOSCHBOTANIC GARDENS
A series devoted to the publication of monographs and major works on southern African flora.
Published: Vols 14-19 (earlier volumes published as Supplementary volumes to the Journal of
SouthAfrican Botany). Discontinued afterVol. 19.
FLOWERINGPLANTS OFAFRICA(FPA)
This serialpresentscolourplatesofAfricanplantswithaccompanyingtext.Theplatesareprepared
mainly by the artists attheNational Botanical Institute. Many botanical artists havecontributedto
the series, suchas FayAnderson, Peter Bally, Auriol Batten, Gillian Condy, Betty Connell, Stella
Gower, Rosemary Holcroft, Kathleen Lansdell, Cythna Letty (over 700 plates), Claire Linder-
Smith andEllaphie Ward-Hilhorst. The Editor is pleased to receive living plants ofgeneral interest
or ofeconomic value for illustration.
From Vol. 55, twenty plates are published at irregularintervals.
An index toVols 1-49 is available.
FLORAOFSOUTHERNAFRICA(FSA)
A taxonomic treatise on the flora ofthe Republic ofSouthAfrica, Lesotho, Swaziland, Namibia
and Botswana. The FSA contains descriptions offamilies, genera, species, infraspecific taxa, keys
to genera and species, synonymy, literature and limited specimen citations, as well as taxonomic
and ecological notes.
Contributions to the FSA also appearin Bothalia.
PALAEOFLORAOFSOUTHERNAFRICA
Apalaeofloraon apatterncomparabletothatoftheFloraofsouthernAfrica. Muchoftheinforma-
tion is presented in the form oftables and photographic plates depicting fossil populations. Now
available:
Molteno Formation (Triassic) Vol. 1. Introduction. Dicroidium, 1983, by J.M. & H.M.
Anderson.
Molteno Formation (Triassic) Vol. 2. Gymnosperms (excluding Dicroidium), 1989, by J.M.
&H.M.Anderson.
Prodromus ofSouth African Megafloras. Devonian to Lower Cretaceous, 1985, by J.M. &
H.M.Anderson.Obtainablefrom:A.A. BalkemaMarketing,Box317,Claremont7735,
RSA.
Towards GondwanaAlive. Promoting biodiversity and stemmingtheSixthExtinction, 1999,
byJ.M.Anderson(ed.)
BOTHALIA
AJOURNAL OF BOTANICAL RESEARCH
Volume 30,1
Scientific Editor: G. Germishuizen
Technical Editor: B.A. Momberg
NASIONALE BOTANIESE
INSTITUUT
Private Bag X101 PRETORISA0001
2000 -05- | 7
Pflvaatsak X101 PRETORIA 0001
national botanical
INSTITUTE
NATIONAL
O T A N I C A L
INSTITUTE
2 CussoniaAvenue, Brummeria, Pretoria
Private Bag X101, Pretoria 0001
ISSN 0006 8241
May 2000
EditorialBoard
D.F. Cutler Royal Botanic Gardens, Kew, UK
B.J. Huntley National Botanical Institute, CapeTown, RSA
P.H. Raven Missouri Botanical Garden, StLouis, USA
J.P. Rourke Compton Herbarium, NBI, CapeTown, RSA
M.J. Werger University ofUtrecht, Utrecht, Netherlands
Acknowledgements to referees
Archer, MrsC., National Botanical Institute, Pretoria, RSA.
Barrington, DrD.S., University ofVermont, Burlington, USA.
Bhat, Prof. R.B., University ofTranskei, RSA.
Boucher, Prof. C., University ofStellenbosch, RSA.
Burgoyne, Ms P., National Botanical Institute, Pretoria, RSA.
Cook, Prof. C.D.K., University ofZurich, Switzerland.
Forster, P.I., QueenslandHerbarium, BrisbaneBotanic Gardens,Australia.
Goldblatt, DrP, Missouri Botanical Garden, StLouis, USA.
Hammer, S., Sphaeroid Institute, Vista, USA.
Hanna, DrW., Coastal Plain Experimental Station, Tifton, USA.
Ihlenfeldt, Prof. H-D., Waabs/Longholz, Germany.
Jordaan, Mrs M., National Botanical Institute, Pretoria, RSA.
Leistner, DrO.A., National Botanical Institute, Pretoria, RSA.
Long, Dr D.G., Royal Botanic Garden, Edinburgh, UK.
Louw, DrA., Nelspruit, RSA.
Manning, DrJ., National Botanical Institute, CapeTown, RSA.
Mucina,Prof. L., KuwaitUniversity. Presentaddress: UniversityofStellenbosch, RSA
Nelson, DrE.C., Outwell, Wisbech, UK.
Oliver, DrE.G.H., National Botanical Institute, CapeTown, RSA.
Phillipson, DrP.B., Rhodes University, Grahamstown, RSA.
Rauh, Prof. W., Heidelberg, Germany.
Retief, Ms E., National Botanical Institute, Pretoria, RSA.
Rourke, DrJ.P, National Botanical Institute, CapeTown, RSA.
Smith, Prof. G.F., National Botanical Institute, Pretoria, RSA.
Steyn, DrE.M.A., National Botanical Institute, Pretoria, RSA.
Thiede, DrJ., University ofCologne, Germany.
Thulin, DrM.L., University ofUppsala, Sweden.
VanJaarsveld, E.J., National Botanical Institute, Pretoria, RSA.
VanWyk, Prof.A.E., University ofPretoria, RSA.
Van Wyk, Prof. B-E., RandAfrikaans University, Johannesburg, RSA.
Verdcourt, Dr B., Royal Botanic Gardens, Kew, UK.
Yatskievych, DrG., Missouri Botanical Garden, StLouis, USA.
CONTENTS
Volume 30,1
New genus, species andcombinations in Bothalia 30,1 (2000) iv
1. Notes onthe genus Frithia (Mesembryanthemaceae) andthe description ofanew species, F. humilis,
in SouthAfrica. P.M. BURGOYNE, G.F. SMITH and F. DUPLESSIS 1-7
2. Areview ofgeneric concepts in the Stilbaceae. J.P ROURKE 9~~
3. Studies in the Sphaerocarpales (Hepaticae) from southernAfrica. 2. The genus Sphaerocarposand its
only local species, S. stipitatus. S.M. PEROLD 17--2.4
4. FSA contributions 15: Piperaceae. K.L. IMMELMAN 25—3^
5. FSA contributions 16: Sphenocleaceae. W.G. WELMAN 31—33
6. Taxonomic studies intheAizoaceae from SouthAfrica: three new species and some new combina-
tions. C. KLAK 35 -U'i
7. Notes onAfrican plants:
Agavaceae.Agave vivipara anaturalised alien in southernAfrica. E.M.A. STEYN and
:
G.F. SMITH 43
Asphodelaceae:Alooideae. The genus Poellnitzia included inAstroloba. J.C. MANNING and
G.F. SMITH 53
Asphodelaceae:Alooideae.Aloedelphinensis inAloe sect. Lomatophyllum. PI. FORSTER ... 53 —
Ericaceae. Two new species ofErica fromWestern Cape, SouthAfrica. E.G.H. OLIVERand
I.M. OLIVER 49-^3
Hyacinthaceae. Correction ofahistorical errorin the taxonomicdescription of Urginea ciliata.
A.P DOLD and R. MOBERG 46 -U-8
8. Morphology and anatomy ofthe rhizome andfrond in theAfrican species ofPolystichum (Pteropsida:
Dryopteridaceae). J.P. ROUX andA.E. VANWYK 57—6c?
9. The epidermis in Passerina (Thymelaeaceae): structure, function and taxonomic significance.
C.L. BREDENKAMPandA.E. VANWYK 69-
10. Vegetation ofthe coastal fynbos androcky headlands southofGeorge, SouthAfrica. D.B. HOARE,
J.E. VICTOR, R.A. LUBKEandL. MUCINA 87-96
11. Checklistofplantspecies ofthecoastal fynbos androcky headlands, south ofGeorge, SouthAfrica.
J.E. VICTOR, D.B. HOARE and R.A. LUBKE 97 - to I
12. Miscellaneous notes:
HyacintL.haucneiaceo.loCr.hrJ.oJm.oSsPoIEmSe,sJt.uLd.ieDsUonPARfErEiZca,nAp.laMntIs.NN13A.ALaRchaenndalRi.aKmuLtEabYilNiHs,ALN.Spustulata and 106- 1lo
Poaceae.Apomicticembryo sac developmentin Cenchrus ciliaris (Panicoideae). N.C. VISSER,
J.J. SPIES and H.J.T. VENTER 103^/o*G
13. Obituaries:
Leslie EdwardWostall Codd(1908-1999). B. DEWINTER and G. GERMISHUIZEN Ill -0S'
Hugh ColinTaylor(1925-1999). D.J. MCDONALD, C. BOUCHERandE.G.H. OLIVER ... 115-110
BarbaraJoanJeppe (1921-1999): botanical artistextraordinaire. G.F. SMITH andE.M.A.
STEYN 119 -111
14. Bookreviews 123
On37E2S©r4 , If I'd . ({suruu.0 1-2.w-
(23,124-
G-, f ;
6LEN , R.,H• f, ' 17.t|
1
New genus, species and combinations in Bothalia 30,1 (2000)
Antimima excedens (L.Bolus) Klak, comb, nov., 35
Astroloba rubriflora (L.Bolus) G.F. Sm. & J.C.Manning, comb, nov., 53
BrownanthusfraternusKlak, sp. nov., 37
Brownanthus glareicolaKlak, sp. nov., 37
Erepsiadunensis (Sond.) Klak, comb, nov., 38
Erica columnaris E.G.H.Oliv., sp. nov., 50
Erica orthiocolaE.G.H.Oliv., sp. nov., 49
Frithiahumilis P.M.Burgoyne, sp. nov., 1
Hammeria meleagris (L.Bolus) Klak, comb, nov., 39
KogelbergiaRourke, genus novum, 12
Kogelbergia phylicoides (A.DC.)Rourke, comb, nov., 13
Kogelbergia verticillata (Eckl. & Zeyli.) Rourke, comb, nov., 12
Scopelogena bruynsii Klak, sp. nov., 39
Stilbe gymnopharyngia (Rourke) Rourke, comb, nov., 11
StilbeoverbergensisRourke, nom. nov., 1
Stilbeserrulata (Hochst.) Rourke, comb, nov., 11
iv
Bothalia30,1: 1-7(2000)
Notes on the genus Frithia (Mesembryanthemaceae) and the descrip-
tion of a new species, F. humilis in South Africa
,
P.M. BURGOYNE*, G.F. SMITH* andF. DU PLESSIS**
Keywords: FrithiaN.E.Br.,Mesembryanthemaceae,newspecies,SouthAfrica,summerrainfallmesembs,taxonomy,windowplants
ABSTRACT
FrithiaN.E.Br.(Mesembryanthemaceae),formerlythoughttobeamonotypicgenus,hasbeenfoundtocomprisetwo
species.PopulationsfromtheeasternpartsofthedistributionrangeofFrithiapulchraN.E.Br.arerecognisedasadistinct
species,FrithiahumilisP.M.Burgoyne.Thegenushasalimiteddistribution,althoughpresentinthreeprovincesofSouth
Africa,namelyGauteng,North-WestandMpumalanga.Thetwowindow-leavedspeciesareallopatricandmorphological
differencesbetweentheroots,leaves,flowers,pollen,capsulesandseedsarediscussed.Aformaldescriptionofthenew
species,anidentificationkeyandadistributionmapofthetwospeciesareprovided.
INTRODUCTIONANDHISTORICALOUTLINE TAXONOMY
The genus Frithia (N.E.Br.) was first mentioned in a To prevent possible confusion with the illegitimate
key by Brown (1925). At that time no species were name Frithia pulchra N.E.Br. var. minor de Boer, the
assigned to the genus and only later was a full descrip- varietalepithetminorisnotusedatthespecificrank.The
tion ofFrithiapulchra given (Brown 1926). The genus name of the new species is derived from the Latin
was namedafterFrankFrith(1872-1954), arailway ser- humilis, which means ‘smallerthan others ofitskind’.
vices gardener stationed at Park Station, Johannesburg.
He was responsible for decorating railway platforms Key to species
from 1900 until his retirement in 1932 (Kroon 1997). In
1906, Olive Nation sent a specimen of a plant she dis- Window ofleaftips convexwith nomarkingsalong margins;
covered near Rustenburg to Brown at Kew for identifi- leaves 15-25mmlong,blue-greenorgrey-green;flow-
ers bright magenta with gold, yellow or white centre,
cation.Thelivespecimendidnotsurvivethejourney,but 25-35mmdiam.;growingwestofPretoriaintheRus-
the remains were seen by Brown who regarded it as a tenburgarea 1.F.pulchra
distinctentity.AfterMissNation died, asearch formore Window ofleaf tips concave with crenulate markings along
material proved unsuccessful. Some time later, a Mrs margins; leaves shorterthan 15 mm, brown-green or
DobieofRustenburgsentplantstoFrankFrith,whotook dullgreen;flowerswhitewithyellowcentre,palepink,
the specimens to Brown at Kew while on a visit to rpairnekl,y1e5nt-i2r0elmympindki,amp.e,talwshesnompeotlilmienastetdiptpuerdnwpiatlhepyaelle-
London, to create the African garden at the Wembley low orsalmon-orange; growingeastofPretoriain the
Exhibition. Dobie’s specimen allowed Brown to finally vicinityofBronkhorstspruitandWitbank 2.F.humilis
describe the genus.
De Boer (1968) published the name Frithia pulchra Frithia humilis P.M.Burgoyne, sp. nov.
var. minor in the Dutch journal Succulenta, but as no
type material was cited the name was invalid. Plants of FrithiapulchraN.E.Br.var.minordeBoer: 147, 148(1968),nom.
illeg.
this variety are generally smaller than those included in
var.pulchra and are restricted to the eastern parts ofthe Plantae perennes nanae succulentae, radicibus succu-
daigsatirnibautlilounderdantgoeboyfHtaherdgyen&us.FaTbhieasne(d1i9f9f2e)r.encZeismmweerr-e lheuntmisumlataerraelnitoesrurmamroestirsa,cttaeemppeorrefolmieisnscoinutmrahctiibleirbnuisulmoni-n
mann (1996) confirmed the different characters of var. gitudinalitervietisfiuntpraesentiaeorundumcavisrelic-
minor, butgave no formal description ortype validating tis indicata. Caulis simplex, brevis, ad 10 mm longus.
the varietal epithet. Although a number ofshort articles Folia spiraliter disposita, obscure virides ad brunneo-
havebeen written onFrithia(Brink 1985; Germishuizen virides, mensisaridishibernispurpureo-suffusa,maxime
1975; Steffens 1988; Venter 1979, 1983), no in-depth succulenta, ad 15 mm longa, cylindrica, idioblastis cera-
study has been done onthe genus.
ceis distincte serialibus, apicibus foliorum fenestratis
cum centra concavo, maculisque conspicuis crenulatis
This paper reports on the taxonomic status of the perimetro. Floressolitares, 15-20mm diametro, albi vel
genus, andspecimensfromtheeasternpartsofits distri- perdilute rosei, centro flavo, ante ad postmeridiem ape-
bution range are formally described as a new species, rientes. Sepala 5, inaequalia, folia simulantia, tubum
Frithiahumilis. brevem connata. Petala 20-30, in verticillis plures dis-
posita, apices plerumque acuminati, interdum rotundati.
Staminodia petaloidea ad filiformia, verticillos aliquot
*NationalBotanicalInstitute,PrivateBagX101,0001 Pretoria.
**DepartmentofBotany,UniversityofPretoria,0002Pretoria. staminum cingentia. Hypanthium basibus connatis
MS.received: 1999-03-15. petalorum staminodium staminumque formatum. Necta-
2 Bothalia30,1 (2000)
ria 5, libra, atroviridia, crenulata. Ovarium supra leviter DISTRIBUTIONANDHABITAT
conicum, stigmata 5 vel 6, perbrevia. Fructuscapsula5-
vel 6-locularis, doliiformis, perfragilis, maturitate Frithia is one of the few genera in the Mesem-
rumpens, semina spargens; valvae ad positionem erec- bryanthemaceae exclusive to the summerrainfall region
tam aperientes, alae valvarum absentes, margines val- ofSouthAfrica. Othermesemb genera with a distinctly
varum recurvati ubi omnis aperti, cristae turgescentes summer rainfall distribution include Neohenricia Mos-
,
pallide luteo-brunneae, apicibus divergentibus margin- sia and Khadia, while Delosperma, Hereroa, Lithops,
ibusque scissis, membranae tegentes ad regulam reduc- Chasmatophyllum, NananthusandStomatiummayoccur
tae.Seminarubro-brunnea,parva,tuberculisparvistecta. in summer rainfall areas but also have wider distribu-
FlorescentiaaDecembri ad Februarium. tions.
—
TYPE. Gauteng, 2528 (Pretoria): Bronkhorstspruit Previously thought to be a monotypic genus and a
Dist., 29 km northeastofBronkhorstspruitontarredroad Magaliesberg endemic, an enlarged Frithia still has a
toVerena,then3 kmalongroadtoSusterstroom,onFarm restricted distribution. Populations of these miniature
Susterstroom, in sandy flat areas associated with rough window plants have been found in two disjunctregions,
rocky outcrops, (-BD), Burgoyne6693 (PRE, holo.). in the North-West between Rustenburg and the Harte-
beespoort Dam in the west, and in an area between
Perennial, dwarf succulent with fleshy roots branch- Bronkhorstspruit (Gauteng)andWitbank(Mpumalanga)
inglaterally;plantsretractingintosandysoilbymeansof in the east(Figure 1). Thetwoareas areroughly 150km
contractile leaves shrinking lengthways during dry win- apart, and so far, no specimens of either species have
ter months, leaving holes marking theirpresence. Stems been collected in the interveningarea.
mm
single, short, up to 10 long. Leaves arranged spiral-
ly, dull green to brown-green with a purple tinge in dry Both species of Frithia grow in very shallow soils
mm
winter months, highly succulent, up to 15 long, derived from coarse sediments: quartzites of the
cylindrical, covered by waxy idioblasts arranged in dis- Magaliesberg Formation of the Pretoria Group of the
tinctrows, tips windowed, withconcavecentre andcon- Transvaal Supergroupin thecase ofFrithiapulchra and
spicuous crenulate markings along perimeter. Flowers sandstones ofthe Irrigasie Formation ofthe EccaGroup
single, 15-20 mm diam., white or very pale pink, with of the Karoo Supergroup for F. humilis. Rocks in both
yellowcentre,openingduringmid-morningtomid-after- areas are very rough, porous and weatherto forma very
noon. Pollinated flowers turn yellow or salmon-orange. coarse gravel.
Sepals 5, unequal, resembling leaves, united to form a
short tube. Petals 20-30 per flower, arranged in several Frithiapulchramostly growsexposedonrockplates,
whorls, tips mostly acuminate, sometimes rounded. the roots anchored in cracks between the coarse
Staminodes petaloid to filiform, surrounding several quartzites.Thissubstratereachesveryhightemperatures
whorls of stamens. Hypanthium formed by fused bases insummer. Plantsarealsofoundincoarsegravel andare
ofpetals,staminodesandstamens.Nectaries5,free,dark not restricted to rocky outcrops. F. humilis grows pre-
green,crenulate. Ovaryslightlyconical above; stigmas5 dominantly in shallow sand along the rims oflarge, flat,
or 6, very short. Fruit a capsule, 5- or 6-locular, barrel- rock plates. Temperatures of the substrate are probably
shaped, veryfragile,breakingupwhenripeandthendis- lower as more organic matter is present, insulating the
persing seeds; valves opening to an upright position, plantbodies againstheatanddessication.
valve wings absent, valve margins recurved when fully
open; expandingkeels lightyellow-brown, parallel, with Both species grow at altitudes ranging from 1 368 m
diverging tips and torn margins; covering membranes to 1 616m, andrainfall variesbetween700and 800mm
reduced to a ledge; closing bodies absent. Seeds red- per annum. Winters are cold and dry and severe frost
brown, small, covered by small tubercles. Flowering occurs in the areas where the plants grow.
time: December-February (summer in the southern
hemisphere).
As the formerly monotypic genus Frithia now has
two species, the type species ofthe genus is Frithiapul-
chra N.E.Br.
SPECIMENSEXAMINED
All specimens held atPRE.
Burgoyne 6692, 6693, 6694, 6694b, 6696, 6698, 6699 (2), 6699b,
6699c(1).
CrundallPRE5498J(2).
Dyer4774(1).Dyer& Verdoorn3922(1).
Gilfdlan7272(2).
Jacobsen758(1).
RoseInnes167(1).
VanPRE54978(1). Venter2997(2). FIGURE 1.—KnowndistributionofFrithiapulchra ,andF. humi-
Young38395(1). lis, •.
—
)
Bothalia30,1 (2000) 3
Other species often associated with both species of
Frithia are the fern ally Selaginella dregei and the
legume Indigofera melanadenia. Species sometimes
found associated with either species of Frithia are the
succulents Anacampseros subnuda subsp. subnuda
,
Crassula lanceolata subsp. transvaalensis,'C. setulosa
var. setulosa and Mossia intervallaris. Monocots like
Microchloa kunthii, Anthericum calyptocarpum together
with an extremely minute and monophyllous species of
Drimia are also found in these habitats. The habitat of
,
Frithiapulchra tends to be drier than that ofF. humilis,
the soils where the latter grow, having a higher organic
content, sometimes resembling peat, and thus retaining
moisture better.
FRITHIA INHORTICULTURE
Frithia pulchra and F. humilis differ widely in their
horticultural history. F. humilis was introduced to the
Dutch seed trade by de Boer thirty years ago and a few
ofthe plants dating from that introduction are still alive.
Thisspeciesisobviouslyquitetolerantanditrespondsto
water more eagerly than does F. pulchra. The latter has
been in continuous cultivation since the late 1920’s but
the plants are usually not long-lived, easily succumbing
to rot. Both species can mature in a few months from
seedunderfavourableconditions,andinthisrespectthey
are typical of a Delosperma alliance. The two species
readily hybridize (S. Hammer pers. comm.) producing
fertile offspring, with a variety offlowercolours includ-
ing orange and bright pink. Many attempts made by
Hammer to hybridize Frithia with other genera (Delo-
sperma Drosanthemum Dorotheanthus, Lithops and
, ,
Fenestraria have always failed, noteven producing the
‘dummy’(empty)fruitswhichoftenresultfromsuchdis-
junct liaisons.
MORPHOLOGICALCHARACTERS
Habit
Both species are dwarf perennials with thickened
roots.Thestemsaremuchreducedandduringperiodsof
drought the plants retract into the sandy soil. This has
been ascribed to contractile roots, but no such roots are
presentineitherspecies.However, inFrithiathecellsof
theleavesarearrangedincolumnar,axialrowsandwhen
moistureis lostand the cells shrink, the tangential walls
contract.Artificially induceddessication usingsilicagel,
indicatedthataleafmaycontracttouptoonethirdofits
length (Figure 2B). This causes the plants to retract into
the soil, a mechanism which renders protection to the
plants during times of drought (Figure 3C). Retraction
intothe groundisthus achieved bymeansof‘contractile
leaves’, notcontractile roots.
Roots
Roots of Frithia pulchra differ from those of F.
humilis in being more fibrous, possibly because of the
FIGURE 2. Frithia pulchra: A, turgid leaf when conditions are
drierconditions prevailing in its habitat and the strategy favourable; B, shrunken leaf under drought conditions C,
rtoockinssuilnasteumtmheer.plants against the heat of surrounding N6e6o9h4ebn:rCi,ciBaursgibobyetnteii6,78le6abf.. ASc,alBeurbgarosy:ne1 m6m6.99c; B, Burgoyne
4 Bothalia30,1 (2000)
—
FIGURE 4. Surface ofleaftips ofFrithia: A, F. pulchra showing
convextipsandnomarkings;B,F. humiliswithconcavecen-
treandcrenulatemarkingsonmargins.A,Burgoyne6699c;B,
Burgoyne6694b. Scalebars: 1 mm.
—
FIGURE3. HabitofFrithia:A, F.pulchra:B,F. humilis',C,plants
of Frithia humilis retract underground during periods of ofF. humilis are tinged brown orpurple. The windowed
drought.Scalebars:A, 10mm;B,30mm;C, 10mm. tipsoftheleaves,however,differconspicuouslybetween
thetwospecies.WindowsofF.pulchraareconvexwhen
Leaves turgid, slightly concave when flaccid (Figure 4A) and
those of F. humilis are concave even when turgid, with
Bornespirally,theleavesofbothspeciesarecylindri- crenulatemarkings(Figure4B)alongthemargins.These
cal with windowed tips andarecoveredby anepidermal leafdifferenceswerealsonotedbyZimmermann(1996).
layerofwaxyidioblastsarrangedindistinctrows(Figure
2(A1)5.-2L5eamvme)s tihnanadiunltF.plhaunmtisliosf(sF.horptuelrchtrhaanar1e5 lmomnge)r. Flowers
Leafcolouralso variesslightly between thetwospecies, Flowers in both species are borne singly and on very
those ofF. pulchra having a bluish tinge, whereas those short stalks or are stalkless. They are subtended by five