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The families of flowering plants

L. Watson and M.J. Dallwitz

Degeneriaceae Bailey & Smith

Habit and leaf form. Large trees; bearing essential oils. Leaves alternate; petiolate; non-sheathing; gland-dotted; aromatic; simple. Lamina entire; pinnately veined; cross-venulate. Leaves exstipulate. Lamina margins entire.

Leaf anatomy. Stomata present; paracytic. Lamina without secretory cavities. The mesophyll with spherical etherial oil cells.

Axial (stem, wood) anatomy. Pith with diaphragms. Nodes penta-lacunar (with five traces). Internal phloem absent. Secondary thickening developing from a conventional cambial ring.

The vessel end-walls oblique; scalariform. The axial xylem with fibre tracheids. The parenchyma mainly apotracheal. ‘Included’ phloem absent.

Reproductive type, pollination. Plants hermaphrodite. Pollination entomophilous; probably via beetles.

Inflorescence, floral, fruit and seed morphology. Flowers solitary (pendulous, on long peduncles); (supra) axillary; medium-sized to large; regular; cyclic; polycyclic. Floral receptacle not markedly hollowed (shortly raised). Free hypanthium absent. Hypogynous disk absent.

Perianth with distinct calyx and corolla; 15–21; 4–6 whorled; isomerous. Calyx 3; 1 whorled; polysepalous; persistent. Corolla 12–18 (the petals larger than the sepals); 3–5 whorled; polypetalous; fleshy; deciduous. Petals sessile.

Androecium about 30–50. Androecial members unbranched; maturing centripetally; free of the perianth; free of one another; 3–6 whorled (?). Androecium including staminodes. Staminodes 3–10 (?); internal to the fertile stamens (located between the stamens and the gynoecium, similar to the stamens but fewer); non-petaloid. Stamens 20–30 (in 3–4 series); laminar (flattened, oblong, three nerved). Anthers adnate (the thecae abaxial); non-versatile; dehiscing via longitudinal slits, or dehiscing by longitudinal valves; extrorse; tetrasporangiate (the four microsporangia paired, abaxial). Microsporogenesis simultaneous. Anther wall initially with more than one middle layer; of the ‘basic’ type. Tapetum glandular. Pollen shed as single grains. Pollen grains aperturate; 1 aperturate; sulcate; 2-celled.

Gynoecium 1 carpelled. The pistil 1 celled. Gynoecium monomerous; of one carpel; superior. Carpel incompletely closed (largely unsealed at anthesis); non-stylate (the stigmatic surfaces running along the apposed margins); about 20–32 ovuled. Placentation more or less marginal (a single row towards each margin of the carpel). Ovules long funicled (in one series), or sessile (in the other); with a conspicuous funicular obturator; anatropous; bitegmic; crassinucellate. Outer integument not contributing to the micropyle. Embryo-sac development Polygonum-type. Endosperm formation cellular.

Fruit non-fleshy (leathery, with a hard exocarp). The fruiting carpel dehiscent, or indehiscent (?). Fruit 20–30 seeded. Seeds copiously endospermic. Endosperm ruminate; oily. Seeds flattened, more or less sculptured, with an orange-red sarcotesta. Embryo well differentiated (but very small). Cotyledons 3(–4).

Seedling. Germination phanerocotylar.

Physiology, phytochemistry. Cyanogenic. Sieve-tube plastids P-type.

Geography, cytology. Paleotropical. Tropical. Fiji. 2n = 24.

Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgren’s Superorder Magnoliiflorae; Magnoliales. Cronquist’s Subclass Magnoliidae; Magnoliales. APG III core angiosperms; Superorder Magnolianae. APG IV Order Magnoliales.

Species 2 (D. vitiensis, D. roseiflora). Genera 1; only genus, Degeneria.

Illustrations. • D. vitiensis, general morphology, pollen: Bailey and Smith, J. Arn. Arb. (1942). • D. vitiensis, stamen details: Bailey and Smith, J. Arn. Arb. (1942). • D. vitiensis, wood anatomy: Bailey and Smith, J. Arn. Arb. (1942). • D. vitiensis, leaf and floral anatomy: Bailey and Smith, J. Arn. Arb. (1942).

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.’.