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A New Species of Microtropis (Celastraceae) from Xizang, China Qinwen Lin and Zhixiang Zhang College of Biological Science and Biotechnology, Beijing Forestry University, P.0. Box 162, Beijing, 100083, People’s Republic of China. [email protected]; [email protected] Abstract. A new species, Microtropis xizangensis Q. usually extra-axillary, lateral, short, < 1 cm; pedun¬ W. Lin & Z. X. Zhang, is described and illustrated. cles ca. 0.5-0.8 cm, apex forked, generally with 3 This species is similar to M. discolor (Wallich) close flowers and 2 bracts; bracts minute, ovate, ca. 1 Wallich ex Meisner in having 4-merous flowers and X 0.5 mm broad, apex obtuse or acuminate. Flower no disk, and differs from it mainly by having 1- to 3- buds (immature) small, ca, 1,5 mm, sessile or shortly flowered inflorescences, non-carinate petals, and pediculale, ellipsoid, ca. 1 mm diam., base with 2 rostrate capsules. The new species is determined as bracteoles; bracteoles minute, ovate, ca. 1 mm, apex Vulnerable (VU) according Lo IUCN Red List round or acute; sepals 4, persistent, slightly incrassate Categories and Criteria, in fruiting, imbricate, unequal, the outer 2 semicir¬ Key words: Celastraceae, China, IUCN Red List, cular or reniform, coriaceous, margin slightly erose, ca. 0.5 X 1 mm, the inner 2 smaller; petals 4, imbricate, white, elliptic, ca. 1 X 0.4 mm, base and The genus Microtropis Wallich ex Meisner (Celas¬ apex round; stamens 4, filaments deltoid, ca. 0.5 mm, traceae) has about 70 species distributed in the warm base ca. 0.1 mm wide, apex acute, anthers small; disk and tropical regions of eastern Asia, southeastern Asia, and Central America (Hou, 1962). The genus is 1.5-2.5 cm, ca. 1 cm diam., verrucose, globose or characterized by its opposite, entire leaves, the elliptic, 1-seeded, base round, apex with long rostra; cymose or thyrsoid inflorescences, the filiform rostra spiculatc, 0.5-1 X ca. 0.2 cm, stipules at the tops of shoots, the 4- to 6-merous bisexual (sometimes unisexual) flowers, the undevel¬ ed to an often inaccessible area of Medog County, oped disks (sometimes absent) with the stamens Xizang. All specimens examined were collected from marginally inserted, and the laterally splitting cap¬ the only location known for Microtropis xizangensis. sules with a single seed. Habitat. Microtropis xizangensis grows in ever¬ Microtropis xizangensis Q. W. Lin & Z. X. Zhang, green broadleaf forest at altitudes from 1300 to sp, nov. TYPE: China. Xizang: Medog, Didong 2100 m. The holotype population was found in evergreen broadleaf forest at 2040 m; other examined 1974 (fr.), Qinghai-Tibet Exped. 1813 (hololype, specimens were discovered in forest areas at 1300 m, KUN; isotypes, KUN [2], PE). Figure 1. 1800 m, 2000 m. and 2100 m. IUCN Red List category. So far there are only seven collections representing Microtropis xizangensis, but two of these have noted that this species common in evergreen broadleaf forest. Considering ellip-ty2i ceml,l omow rdi sihao mbl4g.o,r n-ei7gne, tn em r( n5w—othd)a8eel—lns; stnoputemacl ibefeosr r esoshtf o aucrloedla l enicnot ti oMbneesd, ocgtoh neiss idpceao.rp eu2dl1 a,te3ino4dn4a nkogmfe 2r;te hdiet, isTn ehiwne gnm1ra2aet(ree-g,n1 i 6na) cd eaanuXxtdii raaetl(;el y2,m -)ai3bnda-dr5si be(a -b6aanc)x dui naclelmalayt,er, e r,aac lph esavxlreit giannhcsate lroyr(o5 u wstd,ol ye c7samu cprouraemoinrtihst¬),, HcoVonou uwllntdhee veriensaerbc, r leefi anasc e(ttVo hhreUsu ,)m neMaaan.cr cdxfoiuisrzttduauinrrnebgg,ae nnnscteoiews t oiIr sUot haCdedN e ftc oeorreRnmssetit.dnr u eBcdatL sioeiasndst venation obliquely ascending, arcuate in upper Categories and Criteria (IUCN, 2001). portions, dichotomous at tips, reticulate; petioles No von 18: 498-500. Published on 16 December 2008. doi: 10.3417/2007012 Volume 18, Number 4 Lin & Zhang Microtropis xizangensis (Celastraceae)