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Common name: Dirachma Family.
Number of genera 1. Number of species 2 (Dirachma somalensis D. A. Link, D. socotrana Schweinf. ex Balf. f.).
Angiosperm. Magnoliopsida.
Disseminule a dehisced fruit, or a seed.
Fruits
Pistil(s) compound; 1; 1-pistillate; with carpels united. Fruit pericarpium; simple; capsule; septicidal capsule and septifragal capsule; capsule not inflated; capsule without operculum; with persistent central column; valves diverging from top of central column (resembling umbrella ribs); not within accessory organ(s); more than 1 but less than 10-seeded; 2-seeded; from 1–5 cm long; 1.7–2 cm long; with carpels united; with carpels separating at maturity; with carpels not radiating at maturity; with carpels remaining connected at style; without sterile carpels; apex not beaked; dehiscent. Dehiscent unit seed(s). Dehiscent and shedding seeds; without replum. Epicarp durable; not glabrous (with hairs); hairs medium length (assumed); hairs not glandular; without armature; without wing(s); without apical respiratory hole. Endocarp present; not separating from exocarp; thin; not splitting into 1-seeded pyrenes; smooth; without operculum; without secretory cavities; without mechanism for seedling escape; without grooves; without longitudinal ridges. Funiculus short; short without seed bearing hooks (retinacula); not persisting in fruit after seed shed.
Seeds
Aril absent. Seed larger than minute; elliptic; not bowl shaped; not nutlike; without winglike beak; without caudate appendage(s); without canavanine. Sarcotesta absent. Testa present; without fleshy or leathery layer over hard layer; without glands; without bristles; without wings; without collar; without operculum; colored; monochrome; brown (all shades).
Embryo well developed.
Distribution
Old World. Africa (Somalia: Dirachma somalensis; Socotra: Dirachma socotrana).
Notes
Link (1993): Fruit septicidal-septifragal rostrate capsule packed with long-shaggy hairs becoming detached from base to apex, viz., valves remaining attached at apex. See drawing. Fruit 1.7–2 cm long.
Weed information
No USA noxious weeds.
Listed seeds
No ASOA or ISTA listed seeds.
Accepted genera
Dirachma Schweinf. ex Balf. f.
References specific to this family
Cronquist page 828 (Cronquist & Mabberley have in Geraniaceae). Link, D.A. 1993. 45. Dirachmaceae. In: M. Thulin, ed., Flora of Somalia, vol 1, pp. 191–192. Royal Botanic Gardens, Kew; Thulin, M., B. Bremer, J. Richardson, J. Niklasson, M.F. Fay, & M.W. Chase. 1998. Family relationships of the enigmatic rosid genera Barbeya and Dirachma from the Horn of Africa region. Pl. Syst. Evol. 213:103–119; Link, D.A. 1991. Dirachma somalensis D.A. Link sp. nov. A new species of a remarkable and highly endangered monogeneric family. Bull. Jard. Bot. Natl. Belg. 61:3–13.
General references
Mabberley, D.J. 1987. The plant-book, 706 p. Cambridge University Press, Cambridge.
Illustrations
Fruit and no seed illustrations. Disseminule illustration(s): fruit. Fruit illustration(s): Link (1993). Embryo illustration(s): 12 August 2008. The seeds of Dirachma somaliensis D. A. Link are apparently immature, so I was unable to dissect out the embryo. Joseph H. Kirkbride, Jr.
• Fruit. 1 of 2. Dirachma somaliensis D. A. Link: fruit. • dirach02.gif. 2 of 2.
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, and distributions of character states within any set of taxa. See also Guidelines for using data taken from Web publications.
Cite this publication as: ‘J.H. Kirkbride, Jr., C.R. Gunn, and M.J. Dallwitz. 2000 onwards. Family guide for fruits and seeds: descriptions, illustrations, identification, and information retrieval. Version: 12th April 2021. delta-intkey.com’.
