in J. J. Roemer et al., Syst. Veg. 5: xxxi, 406. 1819.
Herbs, annual or perennial, caudices often branched. Taproots slender, elongate. Stems sprawling to erect, simple or branching proximally or throughout, terete. Leaves opposite or appearing whorled, connate by membranous to thickened line, petiolate or sessile, stipulate (D. pachyphylla not stipulate); stipules 2 per node, white to tan, simple or divided into segments, subulate to filiform, often minute, margins entire, apex acute to acuminate; blade 1–5-veined, linear to lanceolate, spatulate, ovate, reniform, or orbiculate, not succulent, apex rounded to acuminate. Inflorescences terminal or axillary, open to congested, bracteate cymes or umbelliform clusters or flowers solitary, axillary; bracts paired, scarious or central portion herbaceous. Pedicels erect to spreading or reflexed. Flowers: perianth and androecium hypogynous; sepals 5, distinct, white, lanceolate to oblong, ovate, or orbiculate, 1.5–4.8(–5) mm, herbaceous, margins white to purple, scarious, apex acuminate to rounded, hooded or not; petals (3–)5, sometimes absent, white, claw narrow, tapering distally or with oblong or expanded, sessile or short-clawed trunk, auricles absent, blade apex divided into 2 or 4 lobes; nectaries at base of filaments opposite sepals; stamens 5; filaments distinct or briefly connate proximally; styles 3, occasionally 2, connate proximally for 1/2 of length, rarely to nearly distinct (D. cordata), filiform, 0.1–0.3 mm, glabrous proximally; stigmas 3, occasionally 2, linear along adaxial surfaces of styles (or branches), obscurely papillate (30×). Capsules ellipsoid to globose, opening by (2–)3 spreading to recurved valves; carpophore absent. Seeds 3–25, tan, reddish brown, dark brown, black, or transparent (white embryo visible), horseshoe-, snail-shell- or teardrop-shaped, compressed laterally, at least somewhat, tuberculate, marginal wing absent, appendage absent. x = (11), 12.
sw United States, Mexico, West Indies, Central America, South America, introduced in Asia (Indonesia), e, s Africa, Australia, Pacific Islands.
Species 48 (9 in the flora).
Drymaria arenarioides Willdenow ex Schultes, alfombrilla, is on the Federal Noxious Weed List. It is highly toxic to livestock and is native in northwestern Mexico, where it has been reported within a few miles of the United States border.
J. A. Duke (1961) proposed an infraspecific classification for Drymaria consisting of 17 “informal” series that he did not validly publish. Some of Duke’s series were cited by M. Escamilla and V. Sosa (2000), apparently assuming that they were “real” series.
|1||Blades of cauline leaves ovate, deltate, cordate, reniform, orbiculate, or suborbiculate, 4-25 mm wide, base obtuse or cordate to rounded||> 2|
|1||Blades of cauline leaves linear to oblong or lanceolate, 0.2-3 mm wide, base briefly obtuse to attenuate||> 5|
|2||Stems erect or ascending; petals 2-fid, lobe apex not notched; seeds 0.5-0.7 mm||Drymaria glandulosa|
|2||Stems prostrate or sprawling; petals 2- or 4-fid, if 2-fid, lobe apex distinctly notched or seeds 1-1.5 mm||> 3|
|3||Plants glabrous, glaucous, succulent; petals 4-fid; leaves appearing whorled, not stipulate; inflorescences umbelliform clusters||Drymaria pachyphylla|
|3||Plants often glandular in inflorescence, not glaucous, herbaceous; petals 2-fid; leaves opposite, stipules present or deciduous in part; inflorescences open cymes||> 4|
|4||Petals with lobe apex rounded to acute, 1-veined, vein not branched; seeds 1-1.5 mm, tubercles rounded||Drymaria cordata|
|4||Petals with lobe apex distinctly notched, 1-veined, vein dichotomously branched;seeds 0.5-0.7 mm, tubercles conic||Drymaria laxiflora|
|5||Cauline leaves appearing whorled, at least in part||> 6|
|5||Cauline leaves opposite||> 7|
|6||Plants viscid; stems prostrate; sepals stipitate-glandular; inflorescences 4-7-flowered, axillary and terminal cymes||Drymaria viscosa|
|6||Plants glabrous or sparsely glandular; stems erect; sepals glabrous; inflorescences 3-30+-flowered, terminal cymes initially becoming racemose||Drymaria molluginea|
|7||Petals 11/ 1/ 2 times as long as sepals||Drymaria effusa|
|7||Petals 1/ 2-1 times as long as sepals||> 8|
|8||Herbaceous portion of sepals ± oblong, apex blunt or rounded, veins ± parallel, apically confluent||Drymaria depressa|
|8||Herbaceous portion of sepals lanceolate, apex acute to acuminate, veins with lateral pair distinctly arcing outward||Drymaria leptophylla|