Cyperaceae in southern Africa 36: Cyperus marginatus, a complex of three entities

Introduction ( :I'PCI"IfS JlllIrgiJlollIs Thunberg, as the spec ies is presently interpreted. is a widespread taxon reported for all areas of southern Alhea except Botswana (Retief 1993: 103). It is well represented in Namihia (Podlech 1967. 165: 16 and C.J. Ward pers . comm. I 00S). Rid Icy (1884: 136) recorded it for A ngola. On the eastern side or Ihe subcontinent there are, to our knowledge, no ci ted records for t\ lozambique, Zi mbabwe, Zambia or Malawi, but Haines and Lye ( 1983 : 264) include the species for Ke nya where it is 'only known from the Marsabit distr ict' . Plants of the northern provinccs of Sou th Africa are described as · tussocky perennial herbs' of 'temporary wet hab itats' (Retief & Herman 1997: 55): in NataL however, th ey are frequently rooted in shallow. permancntly fl owing waler. often among rocks (Gordon-Grey 1995: 65 ). C larke (1908: (8) placed C margina1us in subgenus PYCI1OSlochys. sec tion Textiles of his conception of (vperus L. , together with ( . a/femi/o/ius L. frolll Madagascar and its allies C jlabelIi/imu;s Rottb . (sic) illegi timate at species level = C ifll'olucralus Rottb . (Kukkonen 1990: 63), C sexal1gll/aris Nees and C lextilis Thullb. Tht': last three species are all southern African and morphologica!ly very alike. It is the length and number of the inflorcscence bracts that differentiate this trio from C. f//argillutlls and the other southern A fri can representatives of section Textiles, namely ( .. dCIIUda/lIs L.f. and C prolfle,. Lam. Collec tively, the section is characterised by reduction of the leaf blades to short ou tgrowths or they may be entirely lacking, the inflorescence bracts, or culms. or bNh these sets o f organs, provid ing the essential photosyntheti c products, Field observation o f plants regularly named C marginallls led one of us (CJW ) to serious ly assess the morphological variation \.\' ithin this taxon and to relate this to known distribution. Preliminary fi nd ings have di sc losed what must be interpreted as three distinct entities, each of which. at the present slage of knowledge. appears worthy of independent specific status but full contirmation must awai t further fiel d study. Awareness of these differing entities is not novel. Early pioneers in Cyperaceae, for example. Nees ( 1835), Kunth (1837), Steudel (18 55) and Boeekele r (1867/8). while accepting Thunberg'S C marginatlls, establi shed and/or maintained olher epithets; most ly at specific rank, 10 accoillmoda te va riants . Among these names are C. blandu.\' KUllt h. Cjim/icola Kunth and C. prionodes Steud . With lapse of lime, these assoc iated taxa have generally come to be treated as synonyms, or varieties, of Thunberg's species under the broad appellation of C marginatlls sensu lalo . There is the typica l entity , the type of which represents Thunberg' s concept of hi s taxon. although the undergro llnd organs that are important in identificati on are lacking. Variety hlmulus (Kunth ) KUkenthal represents a second entity that is more eastern in distri bution. Surprising ly perhaps, il is also present in the Orange River mouth area where the N 0I1hern Cape Province and amibia adjoin (the boundary line between South A fr ica and Namibia bei ng, as yet, not full y settled politically). The third entity is predom inantly western in subcontinen tal southern Africa. It has nol ye t been named nor clearly circumscribed. It is represented by some ear ly gatherings from the Cape Province, for example, Xeyhe/" / 753. Clarke (1893 : 174 ) gives the locality of Zeyher r53 (K ) as 'Calvinia Division, Lospers Flats. 3000-4000 ft.' . whereas the KIRS sheet of th is num ber, wh ich is complete with underground organs present, carries the information ' In salsis ad Spri ngbokk uil (Namaqualand )'. Despi te the apparent local ity difference, both are the same enti ty . JVelw;tsch 6859 from Angola is certainly Entity 3, as Ridley's ( 1884: 136) comment so decisively confirms: 'The old leaf sheaths at the base of the stem break up by decay, leaving only the black wiry fibro-vascular bundles in a tuft . The cul ms are more than three feet in he ight'. Attention Illust be paid to nomenc lature, to trace as far as possible all the earl y names applicable to C morgil1{1/w· in it s widest sense. T his, together with typification, has not been possible for liS. The purpose of th is preliminary paper is merely to dra\v attcntion to the breadth of the 'species ' as it is mostly now interpreted and to circulllscribe the three distinct ent ities we recognise within it. We give somc information on the distribution of these (maps are not reliably informative , as yet) and cite herbarium specimens we have been able to confirm.


Introduction
( :I'PCI"IfS JlllIrgiJlollIs Thunberg, as the spec ies is presently interpreted. is a widespread taxon reported for all areas of southern Alhea except Botswana (Retief 1993: 103). It is well represented in Namihia (Po dlec h 1967. 165: 16 and C.J. Ward pers . comm. I 00S). Rid Icy (1884: 136) recorded it for A ngola. On the eastern si de or Ihe subco ntinent the re are, to our knowledge, no ci ted records for t\ lozambique, Zi mbabwe, Zam bia or Malawi, but Haines and Lye ( 1983 : 264) includ e the species for Ke nya where it is 'onl y know n from the Marsabit distr ict' . Plants of the northern provinccs of Sou th Afri ca are described as ·tu ssocky perennial herbs' of 'temporary wet hab itats' (Retief & Herman 1997: 55): in NataL however, th ey are frequently rooted in shallow. permancntly fl owing wa ler. often among roc ks (Gordo n-Grey 1995: 65 ). C larke (1908: (8) placed C margina1us in subgenu s PYCI1OSlochys. sec tion Textiles of hi s co ncepti on of (vperus L. , together wit h ( . a/femi/o/ius L. frolll Madagascar and its alli es C jlabel- Ii/imu;s Rottb . (sic) illegi timate at species leve l = C ifll'olucralus Rottb. (Kukkonen 1990: 63), C sexal1gll/aris Nees and C lextilis Thullb. T ht': last three spec ies are all so uth ern African and morph ologica!ly very alike. It is the length and number of the inflorcsce nce bracts that differentiate this tri o from C. f//argillutlls and the other southern A fri can rep resent atives of secti on Textiles, namely ( .. dCIIUda/lIs L.f. and C prolfle,. Lam. Collec tively, the section is charac terised by redu ction of the leaf blades to short ou tgrow ths or they may be entirely lac kin g, the infl orescence bracts, or culms. or bNh these sets o f organs, provid ing the essential photosynthe ti c products, Field observati on o f plants regularly named C marginallls led one of us (CJW ) to seri ous ly assess the morphological variation \.\' ithin thi s taxon and to relate this to known distribution. Preliminary fi nd ings have di sc losed what mu st be interpreted as three distinc t e ntiti es, eac h of whi ch. at the presen t slage of know ledge. appears worthy of independent specific status but full contirmati on must awai t further fiel d study. Awareness of these differing entities is not novel. Early pioneers in Cyperaceae, for example. Nees ( 1835), Kunth (1837), Steudel (18 55) and Boeekele r (1867/8). while accepting Thunberg'S C marginatlls, establi shed and/or maintained olher epithets; most ly at specifi c rank , 10 accoillm oda te va riants . Among these names are C. blandu.\' KUllt h. Cjim/icola Kunt h and C. prionodes Steud . With lapse of lim e, th ese assoc iated taxa have generall y come to be treated as sy nonyms, or varieties, of Thu nberg's species under the broad appellation of C marginatlls sensu lalo . There is th e typica l entity , the type of whi ch represe nts Thunberg' s concept of hi s taxon. although the undergro llnd organs that are imp ortant in identificati on are lacking. Variety hlmulus (Ku nth ) KUkenthal represents a second entity that is more eastern in distri bution. Surprisi ng ly pe rhaps, il is also present in the Orange River mout h area where the N 0I1hern Cape Province and amibia adjoin (the boundary line between South A fr ica and Namibia bei ng, as yet, not full y settled politically). The third entity is predom inantly western in subcon tinen tal southern Africa. It has nol ye t been named nor clearly circumscribed. It is represented by so me ear ly gatherings from th e Cape Province, for exam ple, Xeyhe/" / 753. Clarke (1893 : 174 ) gives the locality of Zeyher r53 (K ) as 'Calvinia Di visi on, Lospers Flats. 3000-4000 ft.' . whereas the KIRS sheet of th is num ber, wh ich is complete with undergrou nd organ s present, carries the inform ation ' In salsis ad Spri ngbokk uil (Namaqu aland )'. Despi te the apparent local ity difference, both are the same enti ty . JVelw;tsch 6859 from Angola is certainly Entity 3, as Ridley's ( 1884: 136) co mment so decisi vely confirms: 'T he old leaf sheath s at the base of the stem break up by decay , leaving on ly the black wiry fibro-vascular bundles in a tuft . Th e cul ms are more than three feet in he ight'. Attention Illust be paid to nome nc lature, to trace as far as possible all the earl y nam es appli cable to C morgil1{1/w· in it s wi dest sense. T his, together with typification, has not bee n possi ble for liS. The purpose of th is preliminary paper is merely to dra\v attcntion to the breadth of the 'species ' as it is mo stly now interpreted and to circulllscribe the three distinct entiti es we recognise within it. We give somc information on the distributi on of these (maps are not reliabl y informative , as yet) and cit e herbarium spec imens we have been abl e to confirm.   head-like in fl orc!:icence of severa l apparentty sess ile spi kclets with bracts not clearly surpas si ng these. Basal organs are absent.  waters ( highest recorded sal inity 0.5 parts pe r thousand) . Rhi -7.Olll es are gene rally rooted in damp rocky clay soils or in s ilt and sa nd (all uviulll of old wate rcourses). not in water. In th e Ora nge River m outh area they favour estuarine grass land, or wel l-drained estuarine banks.

Distributi on
T ht: distribution is imperfectly known. Informatio n critically assessed lip to the present tim e shows absence from K waZ ulul .. Nata l: prese nce in the F ree State, nort hern and eastern Cape and Nam ib ia . Record s for the re mai nder o f South A fri ca. Swazila nd and Lesotho require careful checking: field assessment is badly needed .
Selected citations of material studied  S. Ali' 1. Bol. 1999,65(5  The above gatheri ng is almost certainly C. marginailis s.s. It probab ly represent s a robust expression of the entity in it s we ll deve lo ped inflorescences (3 ce ntral head usua lly accompani ed by two or three rays and un usually elongate brac ts). The lea f 377 laminas are also longer than in most specimens. There arc other collections from northern parts of Ih e Eastern Cape (for example. Bark ly East di st rict) that suggest long bracts and fai rly well developed leaf laminas are not exceptional. This need s con fi rmation from further fi eld study. Ward /2-11-1 (N U) provides an example of some of the variabi lity that is often expressed within Entity 1 in the branching of the inflorescence (Figures 18 and 38). In Ward 12~83 (above) the ray le ngth exceeds that of any ray present in Figures I B a nd 38. Occasional specimens of Entity I show evidence of pro liferation by means of shoot devel opment from meri stematic buds within the inflorescence. In the Orange River mouth area occasional plants carry glumes mid brown in colour with a dull surface , co ntrasti ng with ot hers that are more typical. Glu ill e colour variation within Ent ity I needs further assessment to detcrmin e the total range and any possible di stributional and lllicrohabitat relati onships.

Distribution
Li mi ts, at the present state of kn owledge, are uncertain.
Recorded from Swaziland, Leso tho, the area that previously consti tu ted the Transvaa l, especially its eas tern parts, KwaZulu-Natal, the Eastern, Western and Northern Cape and Namibia. So uth Africa, with the poss ibl e exception of KwaZulu-Natal where the entity is qu ite well known, wil l benefit from reassessment.

Habitat
En ti ty 3 is a ' dry land ' plant in compa ri son wi th Ent ities I a nd 2, in that it occurs in sand or rock desert ; b ut al ways in ass oc iation with d rain age lines, tem porarily wet, or temporarily dry . It grows in silt, sand or grave l, mostl y alluvial ; among rocks a long small flow ing stream lets, fringing o ligoh aline springs, o r narrow zones of ri parian woodland.

Distribution
As presen tly known , the di stribution of Entity 3 is predominantly western southern African. It is comm on in Nam ib ia and A ngo la and extends sout hward s to th e Northe rn and Western Cape. Its no rthern limits are not known ; neither is its range in the Karroo and th e Eas tern Cape established . In the northern parts of the Eas tern Cape there appears to be sympatry with Entity 1 and perhaps Entity 2, but field investigation is essenti al to s upport or d iscredit thi s pre liminary deduction. There are other outliers that ind icate p resence towa rds the east. It is not kn own frol11 K w a-Zulu-Nata l, but a co llec tion from Elandskuil, No 2, Ventersdorp difficult to identify as it did not agree with eastern southern African representatives of C marginatlfs. nor precisely with Namibian speci mens. Only mllch later when Entity 3 had been morc intensive ly studied in the field, did it become obvious that C/ Ward and.lf) filard 36 (NU) represented development of a ne\v ramet from the inflo rescence of an already established clone. with the connection died away. Figure 5 exemplifies the extcnt of proliferation that may take place from a compact inf1o~ rescence such as that on the left. Within Entity 3 bracts mayor may not radiate to surpass inflorescence dimensions, but except where inflorescences are extremely dense they can be fairly readily detected: they tend to be depressed towards the cu lm as the inflorescence matures. Young plants, (or plants growing under favourable conditions?) carry leaf blades, often quite wel! developed: but at maturity most plants bear only sheaths enveloping the culm bases.

Discussion and Summary
It is the morpho logical similarity in the organs of reproduction (spikeiets. glumes, nutlets) and possibly the range of variability in the inflo rescence form that has led to the association of three entities under the single spec ies C)'PCI"lIS l1Iorginatlls S.!. How~ ever. even in these organs distinctions exist.
It is ticld investigation that has elucidated more profound di ffere nces . En tity 3 has features that separate it decisively from Entit ies [ and 2: particularly the rhizome with its beards of persistent wiry. dark fibres. This is supported by larger plant size, wider cll[ms hard externally, tending to spiral and to lean before becoming prostrate and rooting. The rhizome, the tall, spongy yet durable culms, the construction of the inflorescence, the lllinutae of spike[ets, g lum e scales and nutlets, and the capacity for pro liferation, are characters that link Entity 3 with Cype/"lIS lexli!;s Thunb. rath er than "'lith Cyperus margil1atlls Entities I and 2. C lexlilis is itself problematic in that it is not adequately d ifferentiated from C ailern{(o/ius L. \vhich is reported from ~Iad agascar. the Mascarene Is [ands, Reunion and Mauritius al1d th at is 110\\ (including variants) \videly cultivated. In the Thun~ berg Herbarium (UPS) nos 1506 and 150 7 are syntypes ofC fex~ liIi.\". Both appear to have been in cultivation 'villa Alwen Smidt' [the llame ditlicliit to decipher] within the general locality 'Cap b. spei'. C rextilis is now widely reported from the Western. Northern and Eastern Cape. It carries lip to 20 or more leafy inflorescence b racts that are never present in Entity 3. This prob~ ably accounts for the placing of Entity 3 with C marginafus rather than with C. texti!;s and its allies, where, from a l11orpho~ logica l aspect. it is better accommodated .
En tity 2 is distinguishable from Entity 1 on its inflorescence forl11 and its spike let shape and usually the spikelet colouration, the g iume scale size and texture and the fruit shape in outline. Up to now, the longer spikelets have been rel ied upon as significant.
s. Afr. J. Bot. 1999.65(5 & 6) but this feature is not satisfactory as elongated spikelets have been observed in all three entities during this study.
The key that follows may be used to differentiate among the entities. It attempts to be comprehensive because al[ aspects of morphological form are not a lways represented in individual her~ barium speci mens that require identification . It, therefore, serves also as a summary of the more important morphological features of each entity.