Scleranthus

Herbs, annual, biennial, or perennial; taprooted or rhizomatous, sometimes stoloniferous. Stems erect or ascending, seldom sprawling, decumbent, or prostrate, simple or branched. Leaves opposite, rarely whorled, connate proximally, petiolate (basal leaves) or often sessile, not stipulate; blade linear or subulate to ovate, not succulent or rarely so (Silene). Inflorescences terminal cymes, thyrses, fascicles, or capitula, or flowers solitary, axillary; bracts foliaceous, scarious, or absent; involucel bracteoles present or often absent. Pedicels present or rarely flowers sessile or subsessile. Flowers bisexual or seldom unisexual (the species then often dioecious), often conspicuous; perianth and androecium hypogynous; sepals 5, connate (1/4–)1/2+ their lengths into cup or tube, (1–)5–40(–62) mm, apex not hooded or awned; petals absent or 5, often showy, white to pink or red, usually clawed, auricles absent or sometimes present, coronal appendages sometimes present, blade apex entire or emarginate to 2-fid, sometimes dentate to lacinate; stamens (5 or) 10 (absent in pistillate flowers), in 1 or 2 whorls, arising from base of ovary; staminodes absent or rarely 1–10; ovary 1-locular, sometimes 2-locular proximally (Vaccaria), or 3–5-locular (some Silene); styles 2–3(–5) (absent in staminate flowers), distinct; stigmas 2–3(–5) (absent in staminate flowers). Fruits capsules, opening by 4–6(–10) valves or teeth; carpophore usually present. Seeds 4–150(–500+), reddish to gray or often brown or black, usually reniform and laterally compressed to globose, sometimes oblong or shield-shaped and dorsiventrally compressed; embryo peripheral and curved, or central and straight. x = 7, 10, 12, [13?,] 14, 15, 17, [18].

Distribution

North-temperate regions, Europe (esp. Mediterranean region), Asia (esp. Mediterranean region e to c Asia), Africa (Mediterranean region, Republic of South Africa).

Discussion

Genera 20 or 26, species ca. 1500 (8 genera, 89 species in the flora).

Caryophylloideae can be characterized by the presence of sepals connate into a cup or (usually) long tube, clawed petals (often with appendages and auricles), and a lack of stipules. The largest genera in the family [Silene (incl. Lychnis), about 700 species; Dianthus, about 320 species] are in the Caryophylloideae; together with Gypsophila (about 150 species), these three genera include about three-quarters of the species found in the family. Three tribes are often differentiated on calyx venation and number of styles, with two, Caryophylleae and Sileneae, incorporating nearly all of the genera.

Caryophylloideae share the caryophyllad type of embryogeny with Alsinoideae and, as postulated by V. Bittrich (1993), the two may form a monophyletic group. Results from preliminary molecular studies by M. Nepokroeff et al. (2002) and R. D. Smissen et al. (2002) reinforce that hypothesis, but the relationships among members of the two subfamilies remain unclear.

Most of the molecular work within the subfamily has focused on Sileneae and more specifically on trying to determine whether or not Silene is monophyletic.

Selected References

Maguire, B. 1950. Studies in the Caryophyllaceae. IV. A synopsis of the North American species of the subfamily Silenoideae. Rhodora 52: 233–245.

Oxelman, B., M. Lidén, R. K. Rabeler, and M. Popp. 2000. A revised generic classification of the tribe Sileneae (Caryophyllaceae). Nordic J. Bot. 21: 743–748.

Lower Taxa

Scleranthus annuus, Scleranthus perennis