Herbs or subshrubs, perennial, non-twining, base woody. Leaves eglandular; stipules interpetiolar, distinct. Inflorescences of chasmogamous flowers terminal, several-flowered umbels or corymbs, or axillary single flowers; of cleistogamous flowers axillary, clusters or single flowers. Pedicels of chasmogamous flowers raised on peduncles, of cleistogamous flowers ± sessile. Flowers chasmogamous and cleistogamous [all chasmogamous]. Chasmogamous flowers 6+ mm diam., showy with visible petals, stamens, and styles; calyx glands 8 or 10 (sepals all 2-glandular or anterior eglandular); corollas bilaterally symmetric, petals carrot yellow or lemon yellow, outermost sometimes with red blotch, glabrous; stamens 5, 3 fertile, opposite anterior and posterior-lateral sepals, 2 staminodial opposite anterior-lateral sepals, (staminodial filaments shorter to somewhat longer than those of fertile stamens), [all fertile]; fertile anthers subequal, staminodial anthers rudimentary; pistil 3-carpellate, carpels nearly distinct in ovary; styles 1(–2)[–3], 1 on anterior carpel, 2d style occasionally on 1 posterior carpel, cylindric; stigmas terminal, capitate or truncate, large. Cleistogamous flowers to 1.5 mm diam., without visible petals, stamens, or styles; calyx glands 0; petals 0 or 1–2, rudimentary; stamens represented by 1–2 minute sessile anthers; pistil 2-carpellate, carpels nearly distinct in ovary; style 0 or 1, rudimentary. Fruits schizocarps, breaking into nutlets (3 in chasmogamous flowers, 2 in cleistogamous flowers); nutlets unwinged, bearing dorsal crest and often narrower lateral crest around periphery; wall thick, tough. x = 40.
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