Tripterocalyx

(Torrey) Hooker

Hooker’s J. Bot. Kew Gard. Misc. 5: 261. 1853.

Common names: Sand -puffs
Etymology: Greek tri, three, pteron, wing, and calyx, in reference to the perianth
Basionym: Tripterocalyx Torrey in J. C. Frémont, Rep. Exped. Rocky Mts., 92. 1843
Treatment appears in FNA Volume 4. Treatment on page 70. Mentioned on page 16.
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Herbs, annual, viscid pubescent to nearly glabrous, from slender or stout and ± woody taproots. Stems decumbent to semierect, unarmed, without glutinous bands on internodes. Leaves petiolate, unequal in size in each pair; blade ± thick and succulent, base usually asymmetric. Inflorescences axillary, pedunculate, capitate clusters; receptacle flat to somewhat rounded-conic, with short, pedicel-like projections; flowers maturing from one side of inflorescence to other; bracts persistent, not accrescent, 5–10, distinct, thin and translucent, forming an involucre, linear-lanceolate to ovate, broad. Flowers bisexual, chasmogamous; perianth radially symmetric, funnelform or salverform, constricted beyond ovary, abruptly expanded to 4–5-lobed limb; stamens (3–)4–5, included; styles included; stigmas linear. Fruits fusiform, indurate throughout, or spongy on exterior, minutely puberulent or glabrous; wings 2–4, translucent, prominently veined, scarious, extending beyond apex and/or base of body; sulci smooth or coarsely rugose.

Distribution

North America (including n Mexico).

Discussion

Species 4 (4 in the flora).

Key

1 Fruits usually with 2 wings, body occasionally ribbed laterally, extending prominently into wings Tripterocalyx crux-maltae
1 Fruits usually with more than 2 wings, body often ribbed laterally, lateral ribs, if extending into wings, only slightly raised > 2
2 Perianth tube 6-18 mm; perianth limb 3-5 mm diam., lobes inconspicous Tripterocalyx micranthus
2 Perianth tube 12-30 mm; perianth limb 8-13 mm diam., lobes over 1.5 mm, showy > 3
3 Perianth limb pale pink to magenta; fruits usually over 20 mm Tripterocalyx carneus
3 Perianth limb white adaxially, white to pink abaxially; fruits usually 20 mm or less Tripterocalyx wootonii