Description

Key Characters:

Growth Form: Evergreen nitrogen–fixing trees or shrubs.

Stems: Branches green, jointed, slender, usually drooping.

Roots:

Leaves: Leaves simple (minute, reduced). Whorled 4–20 per node, ± connate to form a toothed sheath at each node. Blades scale-like. Margins entire. Sessile. Stipules absent.

Flowers: Flowers in staminate flowers in spikes on lateral branches, pistillate flowers in dense, head-like clusters on short lateral branches, staminate flowers consisting of a stamen subtended by a bract and 2 pairs of small bracteoles, the inner pair caducous at anthesis, anthers dithecal, basifixed, opening lengthwise. Flowers unisexual, small and inconspicuous (and the plants monoecious or dioecious). Calyx (sepals) absent. Corolla (petals) absent. Staminate flowers with a single stamen; anthers dithecal, basifixed, opening lengthwise. Ovary superior (pistillate flowers), solitary, 2 carpels, only 1 fertile, the other (usually posterior) usually empty or strongly reduced; ovules 2 in the fertile cell, epitropous or hemitropous, subtended by a scale-like or thickened bract and 2 lateral bracteoles; styles 2, short, terminal; stigmas long, decurrent. Staminate flowers ovary absent.

Fruit: Fruit a 1–seeded; flattened; apically winged nut; the nuts arranged in ovoid or cylindrical; somewhat woody cones; each nut enclosed in the woody bracteoles that separate at maturity and give the appearance of an opened capsules. Seeds with seed coat adnate to pericarp; endosperm absent.

Ploidy:

Habitat:

Elevation Range: