披发南星 pi fa nan xing

Arisaema tsangpoense J. T. Yin & Gusman.

Plants perennial, evergreen, basically dioecious. Rhizome ca. 5 × 2.5 cm. Pseudostem absent. Leaves 1-4 together; petiole dull dark brown to violet, with light brown transverse markings, cylindric, ca. 25 × 0.5-1 cm; leaf blade pedate with 3-5 segments; leaflets petiolulate, greenish, lanceolate, membranous, apex acute ending in a short arista; central leaflet with petiolule to 3 cm, blade ca. 15 × 5 cm, lateral veins numerous, base cuneate; lateral leaflets with petiolule to 5 mm, blade 12-15 × 3-4 cm, base obliquely cuneate. Peduncle whitish, cylindric, much shorter than petioles, ca. 2 × 0.5 cm, surrounded by 3 cataphylls; cataphylls light brown, oblong, ca. 2, 4, and 6 cm, respectively. Spathe: tube white-green, with numerous green longitudinal stripes, cylindric, ca. 3 × 1.5 cm, throat margin widely recurved; limb arched over tube, green, with darker longitudinal veins, ovate-lanceolate, ca. 7 × 4 cm, apex acuminate, ending in a tail ca. 1 cm. Spadix unisexual; female zone conic, 13-15 × 5-10 mm; ovaries congested, green, fusiform, with 1 basal locule, each locule containing 3 ovules, fusiform and slightly curved; stigma disciform, borne on a short style; male zone cylindric, ca. 2 × 0.5 cm; stamens loosely arranged, each consisting of 3-6 anthers, stipitate; thecae yellowish, subglobose, dehiscing by oblong pores; appendix sessile, dark green to purple, slender, 15-40 × 1.5-3 mm, covered with numerous ascending filiform neuter flowers throughout its length; neuter flowers in distal section accompanied by an axillary budlike structure. Fl. Nov.

Forests; 800-900 m. SE Xizang (Mêdog) [S Thailand].

Arisaema smitinandii was recorded from China by H. Li (Aroideana 30: 45-48. 2007). The specimens on which this record was based (Mêdog Expedition 1090, KUN [3 sheets]) are paratypes of the name A. tsangpoense J. T. Yin & Gusman (Ann. Bot. Fenn. 43: 156. 2006; and see subsequent discussion by Gusman, Aroideana 31: 124. 2008). One of us (Murata) agrees with Gusman (loc. cit.) in recognizing the Chinese plants as a distinct species, A. tsangpoense, unique in having a budlike structure present at the axil of the neuter flowers, whereas no such structure has been described or illustrated for A. smitinandii; furthermore, the peduncle is very short in A. tsangpoense but longer than the petiole in A. smitinandii. Murata believes that true A. smitinandii is actually a synonym of A. chumponense Gagnepain, which is endemic to Thailand. On the other hand, one of us (Li) believes that A. smitinandii and A. tsangpoense are conspecific because they have the same filiform neuter flowers on the spadix appendix. Li also believes that the budlike structure at the axil of the neuter flowers is merely an additional neuter flower and that differences in the number and shape of neuter flowers in Arisaema should not be used to distinguish species. Moreover, Li notes that variation in peduncle length is known in other species of Arisaema and, in the case of A. smitinandii, is probably the result of differing climatic conditions in the disjunct areas of the distribution. Li notes a similar disjunction in the distribution of A. cuspidatum Engler, known from the Naga Hills in NE India and from Penang and Selangor in W Peninsular Malaysia. However, P. Boyce (in reviewing this treatment) believes that A. cuspidatum is a junior synonym of A. roxburghii Kunth, which was described from Penang, and that the plant in the Naga Hills is A. album N. E. Brown.