Herbs, annual, perennial, or sometimes biennial, hairy, hairs stellate, 4-rayed, and/or simple, or plants glabrous and glaucous. Stems erect, ascending, or decumbent. Leaves: stipules persistent, caducous, or tardily deciduous, ovate, linear-lanceolate to subulate, auriculate, or rhombic-ovate; blade often pedate, suborbiculate, cordate, ovate, triangular, or hastate, palmately cleft or entire and crenate, base truncate, cordate, or sagittate to hastate, margins 1 per carpel; styles 10–28-branched; stigmas introrsely decurrent, filiform. Fruits schizocarps, erect, not inflated, oblate or depressed-discoid, indurate, reticulate and rugose, strigose or glabrous, indehiscent or dehiscent (annual species only); mericarps 10–28, 2-celled, prominently obtusely beaked or not, drying tan or brown, distal locule sterile, lower 1-seeded. Seeds 1 per locule, reniform or reniform-pyriform (annual species only), glabrous. x = 14, 15.
United States, n Mexico.
Species 9 (9 in the flora).
Several species of Callirhoë are gynodioecious; populations of C. alcaeoides, C. involucrata, and C. leiocarpa have individuals with either bisexual or functionally pistillate (that is, male-sterile) flowers. In these species the functionally pistillate flowers can be recognized by their reduced number of anther sacs, failure of these anther sacs to dehisce, stigmatic lobes often conspicuous at early anthesis, reduced petal size, and in C. alcaeoides shorter calyx lobe length. A few populations of C. pedata in Arkansas exhibit a corolla size dimorphism suggesting that this species too may be gynodioecious. Several species of Callirhoë are cultivated and may escape. All taxa of this genus occur within the flora area except C. involucrata var. tenuissima Palmer ex Baker f., which is wholly Mexican.
|1||Involucellar bractlets (1–)3||> 2|
|1||Involucellar bractlets 0||> 6|
|2||Calyx lobes divergent in bud, not forming point.||Callirhoë involucrata|
|2||Calyx lobes valvate in bud, forming apiculate or acuminate point||> 3|
|3||Involucellar bractlets spatulate or obovate; mericarps dehiscent; leaf blades triangular or ovate-lanceolate, unlobed or shallowly 3- or 5-lobed.||Callirhoë triangulata|
|3||Involucellar bractlets linear, lanceolate, or ovate; mericarps indehiscent; leaf blades cordate, ovate, suborbiculate, hastate, or triangular, 3-, 5-, or 7-lobed||> 4|
|4||Stems 1(–6), stiffly erect, densely hairy (hairs stellate, 6–8-rayed); mericarps hairy.||Callirhoë scabriuscula|
|4||Stems 1–10, weakly erect, ascending, or decumbent, glabrate or hairy (hairs stellate, mostly 4-rayed); mericarps sparsely hairy||> 5|
|5||Leaf blade lobes broad, oblong or obovate; involucellar bractlets lanceolate or ovate, 8–22 × 1–4 mm; stems hairy (hairs stellate, 4-rayed and often simple, spreading or retrorse).||Callirhoë bushii|
|5||Leaf blade lobes narrowly lanceolate, linear, linear-falcate, or lanceolate-falcate; involucellar bractlets narrowly linear, 2–10.5 × 0.1–0.7 mm; stems hairy (hairs stellate, 4-rayed or simple) or sometimes glabrate.||Callirhoë papaver|
|6||Annuals (biennials); stipules auriculate; mericarp beaks subtended by 3-lobed collars.||Callirhoë leiocarpa|
|6||Perennials; stipules linear-lanceolate, lanceolate to ovate or subulate; mericarp beaks subtended by 2-lobed, weakly developed collars or collars absent||> 7|
|7||Mericarps hairy, beaks prominent, protruding beyond seed-containing portions, forming distal 1/4–1/3 of each mericarp||> 8|
|7||Mericarps glabrous or sparingly hairy, beaks not prominent, not or only slightly elevated beyond seed-containing portions, forming less than distal 1/4 of each mericarp||> 9|
|8||Inflorescences racemose; flowers (in population samples) usually bisexual, rarely functionally pistillate; petals usually reddish purple, rarely white or pink.||Callirhoë pedata|
|8||Inflorescences racemose, racemes often appearing corymbose or subumbellate; flowers (in population samples) bisexual or functionally pistillate; petals white, pink, or mauve.||Callirhoë alcaeoides|
|9||Stipules caducous; inflorescences paniculate; leaf blades (3–)5–10-lobed.||Callirhoë digitata|
|9||Stipules persistent; inflorescences racemose; leaf blades 3–5-lobed||> 10|
|10||Stems glabrous; leaf blades with simple hairs abaxially.||Callirhoë pedata|
|10||Stems hairy (hairs stellate, 4-rayed or simple) or sometimes glabrate; leaf blades hairy (hairs 4-rayed and simple) abaxially.||Callirhoë papaver|