Common name. Flax Lilies. Family Phormiaceae.
Sometimes included in Agavaceae.
Habit and leaf form. Shrubs, or herbs. Perennial. Leaves basal, or cauline, or basal and cauline (concentrated at the base or lower part of the stem). Plants with a basal concentration of leaves, or with neither basal nor terminal concentrations of leaves; rhizomatous, or tuberous. Helophytic to xerophytic. Leaves medium-sized to very large; alternate; distichous; commonly leathery (or rigid), or ; ambiguously petiolate to subsessile, or sessile; sheathing. Leaf sheaths with free margins. Leaves edgewise to the stem to with ‘normal’ orientation; simple. Leaf blades entire; flat, or folded; linear; linear; one-veined, or parallel-veined; without cross-venules; sheathing. Leaves without stipules. Leaf blade margins revolute (transversely revolute to complicate). Leaf anatomy. Hairs absent. Extra-floral nectaries absent. Stem anatomy. Secondary thickening absent.
Reproductive type, pollination. Fertile flowers hermaphrodite. Unisexual flowers absent. Plants hermaphrodite.
Inflorescence and flower features. Flowers aggregated in ‘inflorescences’; in cymes (raceme-like), or in panicles. The terminal inflorescence unit cymose. Inflorescences scapiflorous, or not scapiflorous; terminal; inflorescence condensed or loose compound cymose panicle, slender, often much branched, partially bracteate. Flowers pedicellate (articulate below the flower); bracteate (small, scarious), or ebracteate; ebracteolate; small to medium-sized; regular; 3 merous; cyclic; pentacyclic. Perigone tube present (short), or absent. Perianth of ‘tepals’, or with distinct calyx and corolla (dubiously); 6; 2 -whorled; isomerous; petaloid; similar in the two whorls, or different in the two whorls; white, or purple, or blue (usually). Calyx (if the outer whorl so designated) 3; 1 -whorled; polysepalous, or gamosepalous; regular, or unequal but not bilabiate. Corolla (if the inner whorl so designated) 3; 1 -whorled; polypetalous, or gamopetalous; unequal but not bilabiate, or regular; white, or purple, or blue. Androecial members definite in number. Androecium 6. Androecial members free of the perianth; all equal; free of one another; 2 -whorled (3+3). Androecium exclusively of fertile stamens. Stamens 6; all more or less similar in shape; diplostemonous; at the base of the perianth; alterniperianthial. Anthers dorsifixed, or basifixed; dehiscing via pores (often becoming slits), or dehiscing via longitudinal slits; introrse; tetrasporangiate. Pollen shed as single grains. Gynoecium 3 carpelled. The pistil 3 celled. Carpels isomerous with the perianth. Gynoecium syncarpous; eu-syncarpous; superior. Ovary plurilocular; 3 locular (usually); sessile. Gynoecium stylate. Styles 1; attenuate from the ovary; apical. Stigmas 1; capitate. Placentation axile. Ovules 2–12 per locule; arillate, or non-arillate; anatropous.
Fruit and seed features. Fruit fleshy; indehiscent; a berry, or a capsule. Capsules loculicidal, or septicidal. Fruit few per locule. Seeds endospermic. Endosperm oily. Seeds wingless. Cotyledons 1. Testa encrusted with phytomelan.
Geography, cytology, number of species. About 30 species.
Etymology. After Diana, the Roman goddess of hunting, who created queen of the woods by Jupiter, and the diminutive suffix -ell-; the original species was found in woods in southern France; common name in France dianelle des bois.