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The families of flowering plants

L. Watson and M.J. Dallwitz

Dirachmaceae (Reiche) Hutch.

~ Geraniaceae.

Habit and leaf form. Shrubs (with long- and short-shoots); leptocaul. Leaves deciduous; alternate (and clustered on the short-shoots); petiolate; non-sheathing; simple. Lamina entire; lanceolate, or oblong; pinnately veined. Leaves stipulate. Stipules intrapetiolar; free of one another; spiny (subulate); persistent. Lamina margins serrate; flat.

Leaf anatomy. Stomata present; anomocytic, or cyclocytic.

Axial (stem, wood) anatomy. The vessels without vestured pits.

Reproductive type, pollination. Plants hermaphrodite.

Inflorescence, floral, fruit and seed morphology. Flowers solitary; axillary (axillary); bracteolate (the four bracteoles constituting an epicalyx); regular; 8 merous; cyclic; tetracyclic. Free hypanthium present.

Perianth with distinct calyx and corolla; 16; seemingly 2 whorled; isomerous. Calyx 8; seemingly 1 whorled; polysepalous (the sepals subulate); regular; valvate. Epicalyx present (of four bracteoles). Corolla 8; seemingly 1 whorled; polypetalous; contorted; regular.

Androecium 8. Androecial members free of the perianth; all equal; free of one another; seemingly 1 whorled. Androecium exclusively of fertile stamens. Stamens 8; isomerous with the perianth; alternisepalous; opposite the corolla members. Anthers large, oblong-ellipsoidal, dehiscing via longitudinal slits; introrse; bilocular. Pollen grains aperturate; 3 aperturate; colporate.

Gynoecium 8 carpelled. Carpels isomerous with the perianth. The pistil 8 celled. Gynoecium syncarpous; synstylovarious; superior. Ovary 8 locular (and laterally deeply 8-lobed); sessile. Gynoecium stylate. Styles 1; attenuate from the ovary; apical; about as long as the ovary. Stigmas 8; linear. Placentation basal to axile. Ovules 1 per locule; ascending (from the inner angle); anatropous; bitegmic (?); crassinucellate (?).

Fruit non-fleshy; more or less a schizocarp (without a persistent central column). Mericarps 8; comprising follicles (ventrally dehiscent, woolly inside). Seeds scantily endospermic to non-endospermic; compressed. Testa smooth (shiny).

Geography, cytology. Paleotropical. Tropical. Socotra.

Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgren’s Superorder Rutiflorae; Geraniales. Cronquist’s Subclass Rosidae; Geraniales. APG III core angiosperms; core eudicot; Superorder Rosanae; fabid. APG IV Order Rosales.

Species 1 (Dirachma socotrana). Genera 1; only genus, Dirachma.

General remarks. Comparison of this description with that for Geraniaceae (q.v.) using Intkey shows differences in 16 floral morphological characters, in addition to the entire leaves. See Trans. Roy. Soc Edinb. 31, 45, t. 8 (1888) (not yet consulted).

Illustrations. • Dirachma socotrana: Nat. Pflanzenfam. III (1896). • Dirachma socotrana (Hutchinson).

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: 15th April 2018.’.