4. Appendicula annamensis Guillaumin, Bull. Soc. Bot. France. 77: 340. 1930.
小花牛齿兰 xiao hua niu chi lan
Plants lithophytic. Stems tufted, densely leafy, to 33 cm, ca. 1.5 mm in diam. Leaves spreading; blade pale green, drying blackish, ovate-oblong to ovate-elliptic or elliptic, 0.8-1.7 × 0.5-0.8 cm, weakly obtusely bilobed, minutely apiculate. Inflorescences usually pseudoterminal, 5-20 × 5-8 mm, successively ca. 20-flowered but usually with 1-3 flowers open at once; floral bracts ovate, 2-2.5 × 1.5-2 mm, acute, deflexed. Flowers white. Dorsal sepal broadly ovate, ca. 2.5 × 1.8 mm, acute, weakly dorsally carinate; lateral sepals broadly obliquely ovate, ca. 3 × 2.1 mm, subacute; mentum rather tapered, ca. 1 mm. Petals oblong-elliptic, ca. 2 × 1-1.1 mm, obtuse to subacute; lip ca. 3 × 2 mm, subglobose in basal half, in upper half a broadly ovate, subacute epichile; callus retrorse, varying from fleshy, prostrate, flattish, and subquadrate to thinly fleshy, erect, cupulate-concave, and transversely elliptic. Column ca. 1.5 mm including ca. 0.9-mm-long rostellum; foot ca. 1 mm; anther cap lacking a distinct median umbo. Fl. Apr-May.
Lithophytic on rocks on steep slopes. S Hainan [Vietnam].
In October 1937, T. Tang and F. T. Wang determined Fung 20206 (AMES, K), from Hainan, as the Philippine species Appendicula micrantha Lindley. Their determination was eventually published by Merrill and F. P. Metcalf (Lingnan Sci. J. 21: 6. 1945) and followed in FRPS (19: 60. 1999). Ormerod (Taiwania 49: 95. 2004) re-identified Fung 20206, as well as How 72125 (AMES) also from Hainan, as A. annamensis.
Appendicula annamensis differs from A. micrantha in its black-drying leaves, flowers with a slightly more tapered (not squarish) mentum, petals oblong-elliptic (not obliquely obovate-elliptic), dorsal sepal much broader, and anther cap lacking a distinct median umbo.