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The families of flowering plants.                                                                                                                                                                

Degeneriaceae Bailey & Smith

                        

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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.

Stem anatomy. Nodes penta-lacunar (with five traces). Internal phloem absent. Secondary thickening developing from a conventional cambial ring. ‘Included’ phloem absent. Xylem with fibre tracheids; with vessels. Vessel end-walls oblique; scalariform. Wood parenchyma mainly apotracheal. Sieve-tube plastids P-type. Pith with diaphragms.

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, biochemistry. Cyanogenic.

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

Taxonomy.Subclass Dicotyledonae; Crassinucelli. Dahlgren’s Superorder Magnoliiflorae; Magnoliales. Cronquist’s Subclass Magnoliidae; Magnoliales. APG 3 core angiosperms; Superorder Magnolianae; Order Magnoliales.

Species 1. Genera 1; only genus, Degeneria

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