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13. Isatis Linnaeus, Sp. Pl. 2: 670. 1753.
菘蓝属 song lan shu
Herbs annual, biennial, or perennial, often glaucous. Trichomes absent or simple. Stems erect, simple at base, paniculately branched above. Basal leaves petiolate or rarely sessile, rosulate or not, simple, entire, dentate, or pinnately lobed. Cauline leaves sessile and auriculate, sagittate, or amplexicaul at base, rarely petiolate and attenuate, entire or dentate. Racemes many flowered, ebracteate, forming panicles, elongated considerably in fruit. Fruiting pedicels filiform, often thickened and clavate at apex, reflexed. Sepals ovate or oblong, erect or ascending, base of lateral pair not saccate. Petals yellow, as long as or longer than sepals; blade obovate, spatulate, oblong, or oblanceolate, apex obtuse or subemarginate; claw absent. Stamens 6, slightly tetradynamous; anthers ovate or oblong, apiculate or obtuse at apex. Nectar glands confluent, or 4 and median and lateral pairs distinct. Ovules 1(or 2) per ovary, subapical. Fruit indehiscent, samaroid siliques or silicles, oblong, ovate, obovate, cordate, elliptic, oblanceolate, spatulate, or orbicular, strongly angustiseptate, sessile, prominently winged all around or distally, 1(or 2)-seeded, glabrous or hairy, smooth; seed-bearing locule papery or corky, prominently or obscurely 1- or 3-veined, sometimes keeled or shortly winged; valves and replum united; gynophore, style, and septum absent; stigma capitate, entire. Seeds wingless, narrowly oblong, plump; seed coat smooth, not mucilaginous when wetted; cotyledons incumbent or accumbent.
About 50 species: primarily in C and SW Asia; four species in China.
Mature fruit are essential for the reliable determination of species. Leaf, flower, and indumentum characters are unreliable for the determination of Chinese and C Asian species.
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| 1 |
Fruit winged only above the middle, constricted and often curved at middle, spatulate, often with crisped trichomes; petals 1-2 mm |
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4 I. minima |
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Fruit winged all around, not curved and rarely slightly constricted at middle, variously-shaped but not spatulate, trichomes straight; petals (2.2-)2.5-4 mm. |
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(2) |
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| 2 (1) |
Fruiting pedicels slender throughout; fruit oblong-pandurate, densely puberulent with subclavate trichomes, apex emarginate or rarely truncate |
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1 I. violascens |
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Fruiting pedicels clavate at apex; fruit oblong, elliptic, oblong-oblanceolate, or elliptic-obovate, glabrous or pubescent with slender trichomes, apex acute, obtuse, rounded, or rarely subemarginate. |
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(3) |
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| 3 (2) |
Fruit only with a prominent midvein and inconspicuous lateral veins, widest above middle, black or blackish brown |
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2 I. tinctoria |
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Fruit with prominent midvein and two lateral veins, widest at middle, light brown |
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3 I. costata |
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Lower Taxa
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