Plants→ Magnoliophyta → Liliopsida → Alismatales → Hydrocharitaceae Juss. → Maidenia Rendle → Browse taxa…

Maidenia Rendle
J.Bot. 54:316 (1916)

Name Status: Not Current

Scientific Description
H.R. Coleman, Friday 3 October 2008

Family Hydrocharitaceae.

Habit and leaf form. Aquatic herbs. Perennial. Leaves cauline. Plants with neither basal nor terminal concentrations of leaves; stoloniferous. Hydrophytic; non-marine; rooted. Leaves submerged. Not heterophyllous. Leaves alternate (but sometimes appearing almost opposite or whorled, crowded to rather distant); spiral, or distichous; membranous, or ‘herbaceous’; sessile; sheathing to non-sheathing; simple; epulvinate. Leaf blades entire; linear (filiform); one-veined, or parallel-veined; cross-venulate, or without cross-venules. Leaves with stipules, or without stipules. Axillary scales present (1, not fringed). Leaves with a persistent basal meristem, and basipetal development. Stem anatomy. Secondary thickening absent.

Reproductive type, pollination. Fertile flowers functionally male, or functionally female. Unisexual flowers present. Plants dioecious. Female flowers solitary (reaching water surface by elongation of the peduncle); with staminodes (3). Male flowers aggregated in ‘inflorescences’ (flowers shed individually in bud, free-floating on water surface at anthesis). Floral nectaries absent. Pollinated by water.

Inflorescence and flower features. Flowers solitary, or aggregated in ‘inflorescences’. The terminal inflorescence unit (when flowers clustered) cymose. Inflorescences scapiflorous, or not scapiflorous; axillary; the many male flowers (often over 200 per spathe) covering an elongate central axis; pseudanthial (male flowers within the spathe), or not pseudanthial (female flower); spatheate (spathe of the male inflorescence sessile or subsessile, bracts 2, valvate in bud, separated at anthesis, not ribbed). Flowers bracteate (forming ‘spathe’ of female flower, bracts 2, connate in basal half, not ribbed); minute; regular; 3 merous; partially acyclic. The gynoecium acyclic. Perigone tube absent. Perianth of ‘tepals’, or vestigial, or absent (by misinterpretation); 3; 1 -whorled; red to purple. Fertile stamens present, or absent (female flowers). Androecium 3. Androecial members free of the perianth; coherent (the 2 stamens united at the base of their filaments); 1 -whorled. Androecium including staminodes. Staminodes 1. Stamens 2; filantherous. Anthers dehiscing via short slits; extrorse; 3-locular; bisporangiate, or tetrasporangiate. Pollen shed in aggregates. Fertile gynoecium present, or absent (male flowers). Gynoecium 3 carpelled. The pistil 1 celled (with 3 obscure placentae). Gynoecium syncarpous; synovarious to synstylovarious; inferior. Ovary unilocular; 1 locular. Styles 3; free, or partially joined; deeply forked; apical. Stigmas 3; dry type; non-papillate; Group II type. Placentation laminar-dispersed, or parietal. Ovules in the single cavity 12–100 (i.e. ‘many’); pendulous to ascending; non-arillate; orthotropous, or hemianatropous to anatropous.

Fruit and seed features. Fruit fleshy; dehiscent, or indehiscent; withdrawn below the water surface by a spiralling of the peduncle. Dispersal by water. Fruit many-seeded. Seeds endospermic, or non-endospermic; with starch. Cotyledons 1. Embryo straight. Seedling. Hypocotyl internode present. Mesocotyl absent. Seedling collar not conspicuous. Cotyledon hyperphyll elongated; assimilatory; dorsiventrally flattened. Coleoptile absent. Seedling macropodous. Seedling cataphylls absent. First leaf dorsiventral. Primary root ephemeral.

Geography, cytology, number of species. Native of Australia. Endemic to Australia. Australian states and territories: Western Australia and Northern Territory. Northern Botanical Province.

Additional characters Perianth of male flowers vestigial, or absent (by misinterpretation); 3 (representing outer segments, minute). Perianth of female flowers of ‘tepals’; 3 (representing outer perianth segments).

Keys to Maidenia Rendle