Description

Key Characters:

Growth Form: Shrubs, subshrubs, or vines.

Stems: Stems often swollen at the nodes, terete (cylindrical), 4–angled or –ridged, lateral branches of primary stems usually elongating several or more nodes below the inflorescence.

Roots: Roots fibrous or fleshy and thickened (S. membranacea and S. verticillata).

Leaves: Leaves simple. Opposite or in one species occasionally in whorls of 3. Base leaf bases often connate around the stem. Margins entire and often slightly revolute or in basal sections with minute antrorse epidermal protuberances or serrulate, at least in the distal half, sometimes the teeth irregularly spaced and inconspicuous. 1 or 3–12 principal longitudinal veins. Petiolate, weakly to conspicuously connate around the stem. Stipules absent.

Flowers: Flowers in inflorescence terminal, cymoid, flowers in dichasia ( or monochasia by abortion) on the main and upper lateral branches, these forming panicle-like inflorescences, the internodes greatly elongated and inflorescence diffuse, or lateral internodes shorter and the inflorescence contracted, or in two species all internodes extremely reduced and the inflorescence head-like or sometimes (sections alsinidendron and nothoschiedea) the inflorescence appearing to have an axillary origin resulting from the main inflorescence axis completely suppressed, all but the terminal flower borne on lateral inflorescence branches, the flowers pendent, lateral vegetative branches of the next lower node elongating coincident with flowering or nearly so and one of them becoming dominant, assuming subsequent vegetative growth. Flowers bisexual (perfect) and chasmogamous, or unisexual, flowers usually protandrous,// a few species facultatively or obligately autogamous, adapted for insect pollination (in S. menziesii a pyralid moth), //or unisexual (the plants dioecious, subdioecious, or gynodioecious) and adapted for wind pollination or in three species apparently with adaptations for bird pollination, //and in S. diffusa subsp. macraei, S. laui, and S. trinervis cleistogamous. Calyx of (4)5 sepals; sepals green, sometimes purple–tinged, imbricate or in several species broadly so, persistent, reflexed from base or spreading at anthesis, the adaxial face broadly to deeply concave, and weakly or strongly navicular, in some species becoming convex from about the middle to the base, apex acute to acuminate, white with a green tinge or the outermost ones green externally at least toward the base, completely white within, the outer ones ovate, rhombic, oblong or elliptic, the inner ones narrowly obovate to obovate or broadly elliptic, persistent, membranous, becoming papery and not changing color in fruit (sect. Nothoschiedea), or enlarging and becoming fleshy and dark purple (sect. Alsinidendron). Corolla (petals) absent. Stamens (8–) 10 (–12), in 2 series, the antisepalous (inner) whorl inserted on the adaxial face of the nectary near the base or to about ¾ of the way toward the apex, the other (outer) whorl inserted between the nectaries, or (sections Nothoschiedea and Alsinidendron) inserted on the adaxial margin of the nectaries, in dimorphic species all Stamens sterile in pistillate flowers, these usually with empty anther sacs and smaller than fertile stamens; filaments greenish white to yellowish white; anthers yellow, rarely (sections Nothoschiedea and Alsinidendron, and S. stellarioides) pale reddish purple and then often changing to a darker reddish purple, oblong, attached in the lower ⅓ or just below the middle. Pollen 25.7–38.5 μm, yellow to pale yellow or in a few species gray or pale purple. Ovary superior, 1-celled; ovule placentation free-central; styles usually 3, sometimes 4–5, or in a few species 7–11 and then sometimes variable in number within a single plant, filiform; stigma receptive completely around the distal half or rarely nearly throughout its length, slightly enlarged and papillose.

Fruit: Capsules an ovoid to subglobose capsules; enclosed by or exserted from the persistent dried calyx (in section Alsinidendron calyx fleshy and dark purple); dehiscing at maturity by 4–11 valves; or in some species failing to dehisce and seeds dispersing as capsules walls rot. Seeds relatively few to numerous; 0.6–1.8 mm long; the viable ones black or dark or light brown; the inviable ones usually reddish brown; orbicular–reniform; reniform; or rarely orbicular; usually laterally compressed; the surface rugose; papillose; or sometimes nearly smooth; perisperm starchy; hard or rarely soft; true endosperm absent.

Ploidy:

Habitat:

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