Dark Noseburn (Tragia nigricans)
Description
Herbs, 1.5-5.5 dm. Stems erect, purple-green to reddish black, apex never flexuous. Leaves: petiole 1-5 mm; blade oblong to oblanceolate, 3-7 - 1-2.8 cm, base acute to obtuse, margins coarsely serrate, teeth apices often somewhat recurved, apex acute. Inflorescences terminal (appearing leaf opposed), glands absent, staminate flowers 2-5 per raceme; staminate bracts 1-2 mm. Pedicels: staminate 1.3-1.6 mm, persistent base 0.2-0.4 mm; pistillate 2-3 mm in fruit. Staminate flowers: sepals 3-4, green, 1.5-2.5 mm; stamens 4-5, filaments 0.7-1.3 mm, connate 1/2 length. Pistillate flowers: sepals rhombic-lanceolate, 1-4 mm; styles connate 1/4 length; stigmas undulate. Capsules 6-7 mm wide. Seeds dark brown, 2.5-3.2 mm.Flowering spring-summer; fruiting midsummer-fall. Open oak woodlands; 100-700 m; Tex.The combination of relatively large, coarsely serrate leaf blades, dark stems, and filaments connate to 1/2 of length make Tragia nigricans unique within the genus in North America. It appears to be most closely related to T. leptophylla, which also has dark stems and few staminate flowers per inflorescence. Like T. leptophylla, it is found only in the Edwards Plateau, but is restricted to the eastern part; they overlap only in Uvalde County. They also differ in habitat preference.
Taxonomic tree
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Domain: Eukarya
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Kingdom: Plantae
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Phylum: Magnoliophyta
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Class: Magnoliopsida
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Order: Malpighiales
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Family: Euphorbiaceae
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Genus: Tragia
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