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The families of flowering plants

L. Watson and M.J. Dallwitz

Donatiaceae (Mildbr.) Skottsb.

~ Stylidiaceae.

Habit and leaf form. Cushion-forming, mosslike subalpine herbs. Perennial; without conspicuous aggregations of leaves. Mesophytic, or xerophytic. Leaves alternate; spiral; imbricate; non-sheathing; simple; epulvinate. Lamina entire; linear. Leaves exstipulate; leaf development not ‘graminaceous’.

Leaf anatomy. The leaf lamina bifacial (but with palisade only towards the apex). Stomata present; mainly confined to one surface; anomocytic. The mesophyll containing mucilage cells. Midrib conspicuous.

Axial (stem, wood) anatomy. Primary vascular tissues in a cylinder, without separate bundles; collateral. Internal phloem absent. Cortical bundles absent. Medullary bundles absent. Secondary thickening absent (?), or developing from a conventional cambial ring.

The vessel end-walls oblique; scalariform.

Reproductive type, pollination. Plants variously hermaphrodite, or monoecious, or dioecious (?).

Inflorescence, floral, fruit and seed morphology. Flowers solitary; terminal (sessile, sunken among the leaves a the ends of thje branches); regular (in New zealand), or somewhat irregular to very irregular; when irregular, asymmetric. The floral irregularity involving the perianth (the calyx). Flowers cyclic; tetracyclic. Free hypanthium absent.

Perianth with distinct calyx and corolla; 1–20; 2 whorled; isomerous, or anisomerous. Calyx 5–7; 1 whorled; gamosepalous; funnel-shaped to tubular; imbricate, or open in bud (?). Corolla 5–10; 1 whorled; polypetalous; imbricate; fleshy, white; more or less fleshy.

Androecium 2, or 3 (within the low annular disk). Androecial members free of the perianth; all equal; free of one another, or free of one another to coherent (then more or less cohering around the styles); 1 whorled. Androecium exclusively of fertile stamens. Stamens 2, or 3; reduced in number relative to the adjacent perianth. Anthers ovoid, extrorse. Pollen grains aperturate; 3(–4) aperturate; colporate.

Gynoecium 2 carpelled, or 3 carpelled. The pistil 2 celled, or 3 celled. Gynoecium syncarpous; synovarious; inferior. Ovary 2 locular, or 3 locular. Epigynous disk present. Gynoecium stylate. Styles 2, or 3 (one per carpel); basally partially joined, or free; apical. Stigmas 2, or 3; capitate. Placentation axile to apical. Ovules 15–100 per locule (‘many’); non-arillate.

Fruit non-fleshy; indehiscent; capsular-indehiscent. Seeds copiously endospermic. Endosperm oily. Embryo well differentiated (but minute). Cotyledons 2.

Physiology, phytochemistry. Inulin recorded. Iridoids not detected (S.R. Jensen, unpublished).

Geography, cytology. Frigid zone and temperate. Tasmania, New Zealand, subantarctic South America.

Taxonomy. Subclass Dicotyledonae; Tenuinucelli. Dahlgren’s Superorder Corniflorae; Cornales. Cronquist’s Subclass Asteridae; Campanulales. APG III core angiosperms; core eudicot; Superorder Asteranae; campanulid. APG IV Order Asterales (as a synonym of Stylidiaceae?).

Species 2. Genera 1; only genus, Donatia.

General remarks. Comparison using Intkey shows this rather inadequate description differing from that of Stylidiaceae (q.v.) in 12 characters, invoving vegetative, floral and fruit morphology, and biochemistry.

Illustrations. • Donatia fascicularis (Hutchinson). • Donatia novae-zelandiae: Hooker, Fl. Novae-Zelandiae (1853).

We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or 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). See also Guidelines for using data taken from Web publications.

Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 1992 onwards. The families of flowering plants: descriptions, illustrations, identification, and information retrieval. Version: 5th March 2018.’.