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The families of flowering plants

L. Watson and M. J. Dallwitz

Corsiaceae Becc.

~ Burmanniaceae, Orchidaceae.

Including Achratinitaceae Barkley

Habit and leaf form. Reduced, saprophytic herbs. Leaves much reduced (to scales). Plants saprophytic. Perennial; rhizomatous, or tuberous. Mesophytic. Leaves small; alternate; spiral; membranous; sessile; sheathing; simple; epulvinate. Lamina entire; parallel-veined; without cross-venules.

General anatomy. Plants without silica bodies.

Leaf anatomy. Stomata anomocytic.

Axial (stem, wood) anatomy. Cork cambium absent. Secondary thickening absent.

Reproductive type, pollination. Plants hermaphrodite (Corsia), or monoecious.

Inflorescence, floral, fruit and seed morphology. Flowers solitary; terminal; ebracteate; very irregular; zygomorphic. The floral irregularity involving the perianth. Flowers 3 merous; cyclic. Perigone tube present.

Perianth of ‘tepals’; 6; joined; 2 whorled (3+3); isomerous; petaloid; different in the two whorls (in that the posterior member of the outer whorl is large and coloured, and encloses the other five, which are linear-spathulate).

Androecium 6. Androecial members free of the perianth; free of one another; 2 whorled. Androecium exclusively of fertile stamens. Stamens 6; diplostemonous. Anthers dehiscing via longitudinal slits; extrorse. Microsporogenesis successive. Pollen shed as single grains. Pollen grains aperturate; 1 aperturate; sulcate, or ulcerate.

Gynoecium 3 carpelled. Carpels isomerous with the perianth. The pistil 1 celled. Gynoecium syncarpous; synstylovarious; inferior. Ovary 1 locular. Gynoecium stylate. Styles 1; apical. Stigmas 3 (thick). Placentation parietal (the three placentae more or less intruded, two-lobed). Ovules in the single cavity 25–100 (i.e. ‘many’); anatropous; bitegmic; tenuinucellate. Embryo-sac development Polygonum-type. Endosperm formation helobial.

Fruit non-fleshy; dehiscent; a capsule. Capsules valvular. Fruit 25–100 seeded (‘many’). Seeds endospermic. Endosperm oily, or not oily. Seeds minute, or small; winged. Embryo rudimentary at the time of seed release. Testa without phytomelan.

Geography, cytology. Australian and Antarctic. Sub-tropical to tropical. New Guinea, Australia, Solomon Is., Chile. X = 9.

Taxonomy. Subclass Monocotyledonae. Dahlgren et al. Superorder Liliiflorae; Burmanniales. APG 3 core angiosperms; Superorder Lilianae; non-commelinid Monocot; Order Liliales.

Species 10. Genera 2; Corsia, Arachnitis.

Illustrations. • Corsia cordata: Schlechter (1913).

The descriptions are offered for casual browsing only. We strongly advise against extracting comparative information from them. This is much more easily achieved using the interactive key, which allows access to the character list, illustrations, full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, distributions of character states within any set of taxa, geographical distribution, genera included in each family, and classifications (Dahlgren; Dahlgren, Clifford, and Yeo; Cronquist; APG).

Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 1992 onwards. The families of flowering plants: descriptions, illustrations, identification, and information retrieval. Version: 22nd August 2016.’.