Volume 11 > Part 1 > Year 2011 > Page 35 > Lentibulariaceae > Utricularia

19. Utricularia minutissima Vahl

Enum. 1: 204. 1804; A.DC. in DC., Prodr. 8: 16. 1844; C.B.Clarke in Hook.f., Fl. Brit. India 4: 334. 1885; Ridl., Fl. Malay Penin. 2: 492. 1923; P.Taylor in Dansk Bot. Ark. 23: 531. 1968; in Fl. Males., Ser. I, Spermat. 8: 286. 1977; Rani & Matthew in Matthew, Fl. Tamilnadu Carnatic 2: 1117. 1983; Maxwell in Songklanakarin J. Sci. Technol. 7: 419. 1985; P.Taylor, Kew Bull. Addit. Ser. 14: 170. 1989; in Dassanayake & Clayton, Rev. Handb. Fl. Ceylon 9: 177. 1995; Hô, Câyco Viêtnam 3: 111. 1993.

Accepted Name : This is currently accepted.

Synonyms & Citations :

Description : Terrestrial. Stolons few. Rhizoides few, short, unbranched. Floats absent. Leaves narrowly linear, ca (0.6–)1–2.5 cm long, 1-nerved, absent at flowering. Auricles absent. Traps numerous, mostly on stolons and leaves, ca 0.5–1 mm long; mouth lateral, with a single, apical appendage and numerous protruding glands. Internal hairs 2-armed and 4-armed. Inflorescence erect, solitary, usually less than 6 cm long; peduncle rarely hairy, hairs less than 0.1 mm long; usually few 1–3(–6)-flowered; flowers widely spaced. Scales similar to bracts. Bracts attached at the base, narrowly ovate, ca 1 mm long. Bracteoles similar but narrower. Pedicels ca 1(–1.5) mm long in flower, about as long as the bract. Calyx lobes ± equal, 2–3.5 mm long on flowering; ovate, the lower sometimes truncate or emarginate or erose. Corolla blue, purple, pink or white; 2–3(–6) mm long; upper lip very much smaller than lower lip, palate yellow, throat white; spur ca 2–3 mm long, usually pointing downwards, slightly longer than lower lip, straight. Seeds ovoid, ca 0.25 mm long, prominently and coarsely reticulate.

Thailand : NORTHERN: Chiang Mai; NORTH-EASTERN: Loei; EASTERN: Ubon Ratchathani; SOUTH-WESTERN: Kanchanaburi; SOUTH-EASTERN: Sa Kaeo, Chon Buri, Chanthaburi, Trat; PENINSULAR: Surat Thani, Phangnga, Songkhla, Pattani, Narathiwat.

Distribution : India, Sri Lanka, Myanmar, Laos, Cambodia, Vietnam, China, Japan, Peninsular Malasia, Sumatra, Borneo (Sarawak, Sabah), the Philippines, New Guinea (West Papua, PNG), Australia.

Ecology : Moist or wet open areas usually on sandy soil, 0–1,300 m alt. Principally flowering and fruiting: August–December.

Vernacular : Thip keson (ทิพเกสร); ya foi lek (หญ้าฝอยเล็ก)(Loei).

Notes: The black, small, patent hairs, fairly frequently present on specimens of this species are in fact fungal growths and not hairs. However, some Thai material is truly hairy and in one of these specimens the multicellular hairs do reach the calyx lobes; therefore, this specimen is very difficult to separate from Utricularia hirta, though it does lack any long (> 0.2mm) multicellular hairs. Despite its minute size this species is variable in morphology, some Thai material appears intermediate between U. minutissima and U. geoffrayi, being < 6 cm in height, but having a more or less horizontal spur, and a corolla with the lower lip only a little longer than the upper lip. Very rare Thai material from Khao Kuap, Trat has a corolla twice the normal size and is exceptionally tall (10–11 cm tall) but in all other ways is identical to ‘normal’ U. minutissima.