Taxonomical Studies And Molecular Systematical Analysis On Smilax Sect.Macranthae And Sect.Smilax Of Smilax (Smilacaceae)

Phylogeny and systematics of sect. Macranthae and sect. Smilax in the Smilax (Smilacaceae) were investigated based on morphology and molecular data. By separation and combination analyses of nuclear rDNA ITS and the cpDNA (matK gene, rpl16 intron and atpB-rbcL spacer) sequences, the interspecific relationships were discussed, and the classification review and biogeographic analysis were done for all species bearing raceme or spike of one to many umbels with prophylla at base.Koyama (1960) divided Smilax into six sections according to inflorescence and prophylla etc., and defined the sect. Macranthae as with raceme of one to many umbels, defined sect. Smilax as with umbels sessile on elongate. If it is only one umbel, the peduncle has a node or prophylla at the base. After researching on most literatures on Smilacaceae in different floras, observing most of Smilax specimens in the world . deposited in China, Indonesia, Harvard U, NYBBG and NYBG of US, Paris of France, Japan, Berlin of Germany, Spain and Australia, and doing the field collection in South China, Okinawa, Indonesia, Australia, North America, and Spain etc., we have a clear outline of the group, which is about 44 species in the two sections of the world and distributed in almost all of continents: Asia (39 sp.), America (1 sp.), Africa ( 2 sp.), Australia (1 sp.) and Europe (1 sp.). The description and a key of sect. Macranthae species were made in this paper.The molecular trees show that sect. Macranthae is not monophyletic, and some species are embedded in the different clades with the species from different sections. Our results suggested the species of sect. Macranthae are of common ancestor with those of sect. China.The inflorescences of sect. Macranthae are defined as bearing (1-) 2-many umbels racemosely on the peduncle with a prophylla at base. The molecular data supported the standpoint that the raceme of umbels in the sect. Macranthae derives from ancestor by degeneration of leave on basis of each umbel, which is a common character in sect. China and sect. Coilanthns. With the results of ITS and matK gene trees, it is supported that the possible evolutionary tendency of inflorescences is from spike to single umbel and raceme of umbels in Smilax. It has been very clear that the species of sect. Macranthae are a paraphyletic group, which origin from their ancestor at least two times.Comparing the geographic distribution of species from sect. Macranthae and sect. Smilax, there are the phylogenetic relationships and distributive pattern to be found based on the combined ITS and maiK. tree: 1) a clade with the African species (S. kraussiana) and Australian species (S. australis), being a sister group; 2) a clade with the S. zeylanica of sect. Macranthae and S. bona-nox of sect. China, the former from Southeast Asia and latter native to US, showing they are a sister species which is disjunctive between Asia-North America, similar to the species pair of S. hispida and S. sieboldii; 3) S. perfoliata from Indonesia being sister to S. ocreata of China and S. megacarpa of Indonesia, which are very similar to each other in morphology; 4) the three species from China (S. lanceifolia, S. perfoliata and S. chapaensis) and S.ovalifolia from Indonesia showing a 87-92% bts monophyletic clade; 5) S.bracteata from China and two species of Indonesia (S. leucophylla and S. sp.) forming a clade in the ITS tree; 6) S. vanchingshanensis of sect. Macranthae and Heterosmilax yunnanensis forming a perfect monophyletic clade (82-100% bts) based on all molecular trees, appearing a different origin from other species of sect. Macranthae, and supporting sect. Macranthae origins from its ancestor at least two times, also suggested Heterosmilax is not a well supported genus; 7) S. elegantissima may be not a member of sect. Smilax, but it is relation to species of sect. Macranthae As unclear.S. aspera, the most widespread species of the genus, is over three continents (Africa, Europe, and Asia). The molecular trees show the species is a basal group in Smilax phylogenetic tree, and is of a parallel origin with other groups: some species with single umbel and most species with raceme of umbels. The S. zeylanica from Indonesia and S. bona-nox from North America form a new exception over both Asia and America in all gene trees. The S. siphilitia found in Venezuela may be embedded in the clade. This hypothesis would be strengthened if S. siphilitia, the only one American species with raceme of umbels, is sampled and found to be the sister taxon of S. zeylanica and S. bona-nox. The S. kraussiana from Africa and the Australian species S. australis are distantly related morphologically. Based on the molecular tree, it is suggested when they are sister to each other, it does not make sense to say one is from ancestral population in another area, unless the outgroups are from the first area as well.