Onychosepalum Steud.

Scientific Description

Family Restionaceae.

Habit and leaf form. Herbs (with glossy, glabrous cataphylls); evergreen. Switch-plants; with the principal photosynthesizing function transferred to stems (with assimilatory stems). Leaves well developed, or much reduced (the blade being much reduced or absent). Perennial. Young stems cylindrical; not breaking easily at the nodes. Stem internodes solid, or hollow. Rhizomatous. Helophytic to xerophytic. Leaves alternate; distichous, or spiral; leathery, or membranous; sessile; sheathing (and more or less reduced to the sheaths). Leaf sheaths with free margins. Leaves simple; with a persistent basal meristem, and basipetal development. Vegetative anatomy. Plants with silica bodies. Leaf anatomy. Leaf blade epidermis conspicuously differentiated into ‘long’ and ‘short’ cells, or without differentiation into ‘long’ and ‘short’ cells. Guard-cells not ‘grass type’, or ‘grass type’. Stem anatomy. Secondary thickening absent.

Reproductive type, pollination. Fertile flowers functionally male, or functionally female. Unisexual flowers present. Plants dioecious. Female flowers with staminodes, or without staminodes. Male flowers with pistillodes, or without pistillodes. Floral nectaries absent (nectaries absent). Anemophilous.

Inflorescence and flower features. Flowers aggregated in ‘inflorescences’; in ‘spikelets’. Inflorescences scapiflorous, or not scapiflorous; terminal, or axillary; male and female spikelets similar, solitary and terminal or axillary at several upper nodes, lower bracts sometimes sterile; bracts auriculate with a dark, slender mucro. Flowers bracteate; bracteolate, or ebracteolate; cyclic. Perigone tube absent. Perianth of ‘tepals’; members 2–5 (tepals membranous); 2 -whorled, or 1 -whorled; isomerous, or anisomerous; sepaloid. Fertile stamens present, or absent (when female). Androecium 3. Androecial members free of the perianth; free of one another; 1 -whorled. Androecium exclusively of fertile stamens. Stamens 3; oppositiperianthial (opposite the inner perianth members). Anthers dorsifixed; versatile, or non-versatile; dehiscing via longitudinal slits; introrse, or latrorse; bisporangiate, or tetrasporangiate; appendaged, or unappendaged. Pollen shed as single grains. Fertile gynoecium present, or absent (male flowers). Gynoecium 3 carpelled. The pistil 1 celled. Carpels isomerous with the perianth, or reduced in number relative to the perianth. Gynoecium syncarpous; synstylovarious; superior. Ovary unilocular; 1 locular; sessile to stipitate. Gynoecium stylate. Styles 1. Ovules in the single cavity 1; funicled, or sessile; pendulous; non-arillate; orthotropous.

Fruit and seed features. Fruit non-fleshy; indehiscent; a nut (smooth, shed with persistent perianth); 1 seeded. Seeds copiously endospermic. Embryo weakly differentiated. Seedling. Hypocotyl internode absent. Mesocotyl absent. Seedling collar not conspicuous. Cotyledon hyperphyll elongated; assimilatory; more or less circular in t.s. Coleoptile absent. Seedling cataphylls absent. First leaf centric. Primary root ephemeral.

Additional characters Perianth of male flowers of ‘tepals’; 2–5. Perianth of female flowers of ‘tepals’; 2–5. Stems glabrous; simple (with 1-several internodes). Male spikelets several-flowered to many-flowered. Caespitose. Leaf sheaths 0–3.