Taxonomic Study On Eriocaulon (Eriocaulaceae) In China

Eriocaulon L.(Eriocaulaceae)is cosmopolitan and usually found in marshes and water.There are about 400 species around the world,approximately 39-42 of them are found in China.Because of significant interspecific similarities,big intraspecific variations and minute flowers,it is difficult to study the genus Eriocaulon.A taxonomic study was made by observing population variation in field,examining a large number of specimens and reviewing literatures.The main results are as follows:1.Morphology Observation of 12 species(varieties)in EriocaulonAccording to Flora Repubulicae Popularis Sinicae,we classified 39 specimens collected from wild into 12 species(varieties),including E.nantoense Hayata,E.nantoense var.parviceps(Hand.-Mazz)W.L.Ma,E.henryanum Ruhland,E.sexangulare L.,E.setaceum L.,E.pullum T.Koyama,E.yaoshanense var.brevicalyx(C.H.Wright)W.L.Ma,E.merrillii Ruhland,E.merrillii var.longibracteatum W.L.Ma,E.cinereum R.Br.,E.buergerianum Korn,and E.alpestre Hook.f.&Thomson ex Korn..We studied the morphology characters and distributions of them,and discussed the taxonomic issues.Additionally,there are 11 equivocal specimens.2.Taxonomic characters and their taxonomic significanceMorphology characters of the vegetative organs including width,length and veins of the leaves have big variation in E.sexangulare and E.alpestre.So the range of variation should be completely considered when making a taxonomic study.Morphology characters of the reproductive organs including receptacle villous or glabrous,morphology of sepals of male flowers,size of petals of male flowers,each petals of male flowers with a black gland or gland absent,relative length of sepals and petals of male flowers,color of anthers,sepals of female flowers free or connate,numbers of sepals of femal flowers,morphology of sepals of female flowers,morphology of petals of female flowers,petals of femal flowers villous or glabrous,each petals of female flowers with a black gland or gland absent,numbers of ovary locules and morphology of seed testa have important significance in distinguishing species in Eriocaulon.But the receptacle of E.yaoshanense var.brevicalyx is glabrous or occasionally sparsely pubescent.The petals of male flowers of E.merrillii,E.cinereum,E.nantoense,E.alpestre are very small and variational,so it is difficult to compare the size of them.The glands of petals of male flowers of E.nantoense var.parviceps and E.merrillii var.longibracteatum are absent or present.The sepals of female flowers are 2 or 3 in E.sexangulare and E.cinereum.The petals of female flowers of E.alpestre are glabrous or villous.The seed testa of E.merrillii var.longibracteatum is hexagonally reticulate,and cells longitudinally elongate or quadrangular,quinquanqular with ribbonlike bands from longitudinal wall.The seed testa of E.cinereum is hexagonally,quadrangularly or quinquanqularly reticulate,and cells longitudinally or transversely elongate.The prickles of the seed testa of E.alpestre are T-shaped,Y-shaped or linear.So the range of variation should be completely considered when making a taxonomic study.3.Geographical distribution of Eriocaulon in ChinaBased on field collection and combined with literature and the specimens of CCNU,PE and CVH,the geographical distribution of Eriocaulon in China were studied.The results showed that,40 species of Eriocaulon can be generalized 7 geographical distribution patterns.E.cinereum has Cosmopolitan distribution pattern.E.australe and E.setaceum have Trop.Asia&Trop.Australasia distribution pattern.E.sollyanum has Trop.Asia to Trop.Africa distribution pattern.E.angustulum,E.henryanum,E.brownianum,E.brownianum var.nilagirense,E.sexangulare,E.yaoshanense var.brevicalyx,E.zollingerianum,E.merrillii and E.echinulatum have Trop.Asia distribution pattern.E.alpestre,E.robustius,E.chinorossium and E.decemflorum have Temp.Asia distribution pattern.E.senile,E.buergerianum and E.sikokianum have Asia distribution pattern.E.acutibracteatum,E.nantoense,E.nantoense var.micropetalum,E.nantoense var.parviceps,E.rockianum,E.rockianum var.latifolium,E.schochianum,E.pullum,E.yaoshanense,E.bilobatum,E.leianthum,E.merrillii var.longibracteatum,E.sclerophyllum,E.taishanense,E sikokianum var.linanense,E.alpestre var.sichuanense,E.glabripetalum,E.minusculum,E.faberi and E.mangshanense have Endemic to China distribution pattern.