POSIDONIACEAE [Draft]

波喜荡科 BO XI DANG KE

Guo Youhao(郭友好)[1], Robert R. Haynes[2], C. Barre Hellquist[3]

Herbs perennial, submerged, marine, with creeping rhizome and short, erect stems. Rhizomes and stems with dense, persistent, fibrous leaf bases. Leaves basal, alternate, sheathed at base; sheaths convolute, auriculate at base, apex ligulate. Inflorescence of 1 or more aggregated spikes  on elongated peduncle, subtended by reduced leaves (leaflike bracts); flowers bisexual or  uppermost with a reduced gynoecium. Perianth absent or of 3 caducous scales. Stamens 3; anthers sessile, extrorse, with a thick connective, opening by longitudinal slits; Carpel 1, ovule 1, elongated. Fruit fleshy, indehiscent. Seeds without endosperm; embryo straight.

One genus with about five species; one species in Mediterranean, others on shores of W Pacific Ocean; only one species in China.

1. POSIDONIA K. König, Ann. Bot. (König& Sims.) 2: 95. 1805(‘1806’), nom. cons.

波喜荡属  bo xi dang shu

Description and distribution as for the family.

1. Posidonia australis J. D. Hooker, Fl. Tasman. 2: 43. 1858.

波喜荡  bo xi dang

Leaves linear, often slightly falcate, flat, 60–90 × 0.6–1.5 cm, 11–21-veined, margin entire, apex rounded or truncate; sheaths ca. 12 × 1 cm, margins inflexed, auriculate above. Inflorescences with 2–7 spikes together terminal on a leafless stem; leaflike bracts similar to leaves but small, with ± reduced blade; spikes 3–7.5 cm, 3–6-flowered. Anthers reddish, with a thick, ovate-lanceolate connective; pollen grains filiform. Carpels 4–5 mm; stigma sessile, irregularly lobed. Fruit green or yellowish green, obliquely obovoid, 1.5–3 cm. 2n = 20.

Marine, sandy bottoms near low tide mark. Hainan (Sanya) [Shores of W Pacific Ocean and Coasts of Australia].

 



[1] Herbarium or Wuhan University, Department of Biology, Wuchang, Hubei, People’s Republic of China

[2] Herbarium, Biological Sciences, Biodiversity and Systematics Department, University of Alabama, Box 870345, Tuscaloosa, Alabama 35487-0345, U.S.A.

[3] Department of Biology, Massachusetts College of  Liberal Arts, North Adams, Massachusetts 01247-4100, U.S.A.