Family Drosophyllaceae

Drosophyllaceae Chrtek, Slaviková & Studnicka

Habit and leaf form. Shrubs, or herbs (somewhat woody). Plants ‘carnivorous’. Trapping mechanism active. The traps constituted by sticky leaf glands, associated with subsequent, slow enclosure of the prey by movement of the blade (with stalked and sessile glands secreting digestive ferment, cf. those of Drosera, but in this plant the stalked ones have no power of movement). Perennial; with a basal aggregation of leaves; rhizomatous. Mesophytic to xerophytic (growing in dry, alkaline soils). Leaves marcescent; small to medium-sized; crowded, alternate; spiral; non-sheathing; simple. Lamina entire; linear (linear-elongate, basally and apically attenuate). Leaves without a persistent basal meristem. Vernation circinnate; outwardly circinnate (seemingly a unique condition, and contrasting with the inwardly circinate leaves of Drosera spp.).

Stem anatomy. Secondary thickening absent.

Reproductive type, pollination. Plants hermaphrodite. Pollination entomophilous.

Inflorescence, floral, fruit and seed morphology. Flowers aggregated in ‘inflorescences’; in corymbs. The ultimate inflorescence unit racemose. Inflorescences wide corymbs. Flowers medium-sized to large (to 4 cm in diameter); regular; 5 merous; cyclic; tetracyclic, or pentacyclic (? - depending whether there are two whorls of stamens). Free hypanthium absent. Hypogynous disk absent.

Perianth with distinct calyx and corolla; 10; 2 whorled; isomerous. Calyx 5; 1 whorled; shortly gamosepalous. Calyx lobes markedly longer than the tube (acute). Calyx regular; persistent; imbricate. Corolla 5; 1 whorled; polypetalous; regular; yellow.

Androecium 10–20. Androecial members free of the perianth; all equal; free of one another; 1 whorled, or 2 whorled (?). Androecium exclusively of fertile stamens. Stamens 10–20; isomerous with the perianth, or diplostemonous; filantherous (the filaments basally compressed). Anthers dehiscing via longitudinal slits; extrorse; tetrasporangiate. Endothecium developing fibrous thickenings. Microsporogenesis simultaneous. The initial microspore tetrads tetrahedral, or isobilateral. Anther wall initially with one middle layer; of the ‘monocot’ type. Pollen shed as single grains. Pollen grains aperturate; 3-celled.

Gynoecium 5 carpelled. Carpels isomerous with the perianth. The pistil 1 celled. Gynoecium syncarpous; synovarious; superior. Ovary 1 locular. Gynoecium stylate. Styles 5; free; apical. Stigmas 5; large, capitate. Placentation basal. Ovules in the single cavity 10–100 (i.e., many); ascending; non-arillate; anatropous; bitegmic. Outer integument not contributing to the micropyle. Embryo-sac development Polygonum-type. Polar nuclei fusing prior to fertilization. Antipodal cells formed; 3; not proliferating; ephemeral. Synergids hooked (with filiform apparatus). Endosperm formation nuclear.

Fruit non-fleshy; dehiscent; a capsule. Capsules papery, valvular. Dispersal unit the seed. Fruit 10–50 seeded (i.e., many-seeded). Seeds copiously endospermic; quite large, obovate, compressed and angled. Embryo well differentiated (small). Cotyledons 2. Embryo straight (?).

Physiology, biochemistry. Inulin recorded (Gibbs 1974). C3.

Geography, cytology. Holarctic. Sub-tropical. Spain, Portugal and Morocco.

Taxonomy. Subclass Dicotyledonae; Tenuinucelli. Dahlgren’s Superorder Theiflorae; Droserales. Cronquist’s Subclass Dilleniidae; Nepenthales. APG 3 core angiosperms; core eudicot; Superorder Caryophyllanae; Order Caryophyllales.

Species 1. Genera 1; Drosophyllum (D. lustitanicum).

This curious, ostensibly Drosera-like carnivorous monotypic is now regarded as a caryophylloid relative of Ancistrocladaceae and Dioncophyllaceae.