Family Ecdeiocoleaceae

Ecdeiocoleaceae Cutler & Airy Shaw

~ Restionaceae

Habit and leaf form. Herbs. Switch-plants. Leaves much reduced. Perennial; with neither basal nor terminal aggregations of leaves; rhizomatous. Xerophytic. Leaves alternate; distichous; membranous (reduced to scales); sessile; sheathing. Leaf sheaths with free margins. Leaves simple; epulvinate. Lamina entire; parallel-veined; without cross-venules. Leaves eligulate.

General anatomy. Plants with silica bodies (as silica sand, in the culm mesophyll). Chlorenchyma including ‘peg cells’.

Leaf anatomy. Epidermis without differentiation into ‘long’ and ‘short’ cells; without silica bodies. Stomata paracytic. Guard-cells ‘grass type’.

Lamina without secretory cavities. The mesophyll not containing mucilage cells; without calcium oxalate crystals (? — no raphides). Vessels absent.

Stem anatomy. Young stems cylindrical (grooved, wiry). Secretory cavities absent. Secondary thickening absent. Xylem with vessels. Vessel end-walls scalariform and simple.

Root anatomy. Root xylem with vessels; vessel end-walls scalariform and simple.

Reproductive type, pollination. Plants monoecious (male and female flowers in the one spikelet). Female flowers with staminodes (three). Gynoecium of male flowers pistillodial. Floral nectaries absent (nectaries absent). Pollination anemophilous.

Inflorescence, floral, fruit and seed morphology. Flowers aggregated in ‘inflorescences’; in spikes; in effect, in ‘spikelets’. The ultimate inflorescence unit racemose. Inflorescences terminal; small, solitary, terminal spikes — constituting spikelets; espatheate (i.e. no basal sheathing bract, by contrast with Restionaceae). Flowers bracteate (with basal ‘glumes’); ebracteolate; minute; 3 merous; cyclic. Perigone tube absent. Hypogynous disk absent.

Perianth of ‘tepals’; 6; free (somewhat unequal); 2 whorled (3+3); isomerous; sepaloid (glumaceous); different in the two whorls (two members of the outer whorl being laterally compressed and ciliate towards their tips).

Androecium of male flowers, 6. Androecial members free of the perianth; all equal; free of one another. Androecium of male flowers exclusively of fertile stamens. Stamens 6; isomerous with the perianth, or diplostemonous; oppositiperianthial. Anthers basifixed; non-versatile; dehiscing via longitudinal slits; tetrasporangiate. Pollen grains aperturate; 1 aperturate; ulcerate. The ulcus operculate; with an annulus. Interapertural exine not scrobiculate. Interapertural interstitium columellate.

Gynoecium 2 carpelled. The pistil 2 celled. Gynoecium syncarpous; synovarious; superior. Ovary 2 locular. Styles 2; free; attenuate from the ovary; apical. Stigmas 2 (the styles stigmatic to near the base). Placentation apical. Ovules differentiated; 1 per locule; pendulous; non-arillate; orthotropous. Outer integument contributing to the micropyle. Synergids non-haustorial.

Testa without phytomelan (?).

Geography, cytology. Western Australia.

Taxonomy. Subclass Monocotyledonae. Dahlgren et al. Superorder Commeliniflorae; Poales. APG 3 core angiosperms; Superorder Lilianae; commelinid Monocot; Order Poales.

Species 1. Genera 1; only genus, Ecdeiocolea.