独龙枫 du long feng

Acer taronense Handel-Mazzetti, Anz. Akad. Wiss. Wien, Math.-Naturwiss. Kl. 61: 84. 1924; A. chloranthum Merrill; A. laxiflorum Pax var. longilobum Rehder; A. pectinatum var. longilobum (Rehder) A. E. Murray; A. tegmentosum Maximowicz subsp. rufinerve A. E. Murray.

Trees to 20 m tall, andromonoecious. Petiole 2-6 cm, densely rufous pubescent when young, less so when mature; leaf blade triangular-ovate or ovate-oblong, 6-15 × 4-9 cm, abaxially densely rufous pubescent on veins when young, base cordate or subcordate, margin doubly serrulate with adpressed acute teeth, 3- or 5-lobed; middle lobes triangular-ovate, apex acuminate; lateral lobes acuminate apically; basal lobes small, apex acute or obtuse. Samara wings spreading obtusely. Fl. Apr-May, fr. Aug-Sep.

Mixed forests; 2300-3000 m. W Sichuan, E Xizang, NW Yunnan [Bhutan, NE India, NE Myanmar].

One of us (de Jong) noted that Acer chienii is indeed different from this taxon. At first look, it is very similar to A. rufinerve Siebold & Zuccarini. At Caerhays Castle (U.K.), both A. taronense and A. chienii (labeled A. taronense) grow side by side, and they are very different. Acer chienii has typically tulip-shaped leaves that are very rufous beneath; it is listed as a species in Flora Yunnanica.

One of us (Chang) believes that this subspecies falls within the pattern of variation found in Acer pectinatum. According to examination of specimens of A. chienii preserved at PE, the inflorescence is 20-25-flowered, but the type specimen has only 10-15 flowers per inflorescence. It seems that this name has been misapplied to A. forrestii collected from these areas. Acer chienii seems to belong to the pattern of morphological variation of A. pectinatum. However, one of us (Chen) believes that flower number is not a very important character; specimens in many species vary in flower number (including A. chienii and A. pectinatum subsp. taronense).