Stylidiaceae [DRAFT]
花柱草科 hua zhu cao ke
Hong Deyuan (洪德元)[1]; Juliet Wege[2]
Herbs or small shrubs, some members mosslike, without laticifers. Stipules absent. Leaves alternate, simple, often grasslike. Inflorescence a raceme, cyme, or lax spike. Flowers perfect or unisexual, zygomorphic. Calyx and corolla 5-merous. Calyx synsepalous; tube adnate to ovary; limb often 2-labiate, with 2--5 lobes; lobes imbricate. Corolla synpetalous, often irregular, 5(or 6)-lobed; 4 lobes similar but anterior one (labellum) often different in shape and reflexed. Stamens 2, at lateral sides, adnate with style, forming a gynostemium; anthers extrorse, 2-celled. Ovary inferior, 2-locular, incompletely 2-locular, or even 1-locular due to reduction of septum; ovules usually numerous, on axile or free-central placentas, anatropous; stigma entire or 2-fid, adnate with anthers. Fruit a capsule, usually septicidal. Seeds few to more often numerous, minute; seed-coat thin; embryo small, embedded in copious endosperm.
Protandrous and entomophilous; gynostemium often irritable, normally bent to labellar side but snapping to an oppositely bent position when touched.
Four or five genera and ca. 150 species: Australia, New Zealand, S end of South America with only Stylidium extending into tropical Asia; one genus and two species in S China.
1. Stylidium Swartz ex Willdenow, Sp. Pl., ed. 4, 4: 7, 146. 1805, nom. cons.
花柱草属 hua zhu cao shu
Herbs, annual or perennial, often covered with glandular hairs. Leaves alternate, simple, cauline or in a basal rosette. Inflorescences a cyme, raceme, or lax spike, terminal. Flowers perfect, zygomorphic. Calyx anterior 2 lobes often connate into a shallowly 2-lobed segment. Corolla irregular, lobes distinct or 2 or 4 connate, anterior one small and reflexed; corona often present, formed by glandular appendix at throat. Stamens at lateral sides, completely adnate with style, forming a long gynostemium usually exserted from corolla, bent and irritable, base movable; anthers sessile, just below stigma. Ovary 2-locular or partially 1-locular; ovules numerous.
About 120 species: Australia, tropical Asia; two species in S China.
Almost all species occur in Australia with Asia only having 8 species of which four are endemic to Asia.
1a.. Leaves basal, with a short petiole; leaf blade ovate-orbicular, ovate, or obovate .................. 1. S. uliginosum
1b.. Leaves cauline, sessile; leaf blade oblong-obovate to lanceolate ................................................. 2. S. tenellum
1. Stylidium uliginosum Swartz, Ges. Naturf. Freunde Berlin Mag. Neuesten Entdeck. Gesammten Naturk. 1: 52. 1807.
花柱草 hua zhu cao
Stylidium sinicum Hance.
Herbs, annual, 5--13 cm tall. Leaves all basal, with a short petiole; leaf blade ovate-orbicular, ovate, or obovate, 5–8 mm, glabrous, veins obscure, margin entire, apex obtuse to rounded. Stems 1--3, leafless, simple or dichotomously branched, covered with sparse short glandular trichomes. Inflorescences a long and lax spike; bracts ovate, less than 1 mm. Flowers small, sessile. Calyx tube (hypanthium) narrow, with sparse glandular trichomes; lobes minute, anterior 2 connate into a shallowly 2-lobed segment ca. 1.8 mm but others 3 linear and ca. 1.2 mm. Corolla white, ca. 2 mm; tube short; anterior lobe extremely small, ovate, reflexed, becoming a labellum; 4 remaining lobes patent toward posterior side with 2 most posterior longer, base with an appendix, apex shallowly 2-lobed. Gynostemium ca. 3.5 mm, exserted. Ovary 2-locular. Capsule columnar, ca. 8 mm.
Moist grassy places by streams in coastal hilly areas. Guangdong, Hainan [NE Australia, Sri Lanka].
2. Stylidium tenellum Swartz, Ges. Naturf. Freunde Berlin Mag. Neuesten Entdeck. Gesammten Naturk. 1: 51. 1807.
狭叶花柱草 xia ye hua zhu cao
Herbs, annual, erect, 5--20 cm tall. Stems slender, simple or laxly dichotomously branched, glabrous. Leaves alternate, few, sessile or nearly sessile; leaf blade oblong-obovate to oblanceolate, 6--10 mm, apical ones smaller and gradating into bracts, glabrous, veins 3 inconspicuous and arcuate, base cuneate, margin entire, apex obtuse. Inflorescences terminal. Flowers solitary, in a spike of 2 or 3, or in a dichotomous inflorescence, sessile. Calyx glabrous or with glandular trichomes; tube (hypanthium) elongate, ca. 1 cm; 2 lobes connate into a slightly 2-lobed segment. Corolla white or rose purple, less than 2 mm, with sparse glandular trichomes; tube slightly longer than calyx-lobes; lobes distinct, posterior one 2-lobed, anterior ones much smaller; labellum minute, subulate; appendix at throat minute but visible. Capsule thinly columnar, to 2 cm.
Paddy fields, swamps; below 1000 m. S Fujian, Guangdong, Hainan, Yunnan (Xishuangbanna) [Cambodia, Indonesia, Laos, Malaysia, Myanmar, Vietnam].