Daleae Imagines page 709 plate LVIII
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Title
Daleae Imagines page 709 plate LVIII
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Creator(s)
R. C. Barneby
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Publisher
The New York Botanical Garden Press
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Description
PLATE LVIII Dalea purpurea Ventenat, prototype of the purple prairie-clovers, a polymorphic species dispersed over the prairies from s.-w. Canada to n.-e. New Mexico and n. Texas, e. to the Ohio River and centr. Alabama, and the related D. compacta Sprengel of centr. and e. Texas and adjoining states, differing in the larger calyx, glabrate externally except for lines of silvery pubescence leading to the sinuses between the teeth. In the Mississippi Valley typical D. purpurea is commonly a tall virgate herb (to 9 dm), the stems branching at the top into a panicle of few or several heads; w.-ward it is represented by mostly dwarfer forms, often diffuse, commonly monocephalous. The foliage is inconspicuously pilosulous, seldom glabrous, rarely gray-pilose. Over most of the range the relatively massive spike is elevated little above the leaves but on the short-grass prairies between w. Kansas and n.-w. Texas the dominant form is var. arenicola (Wemple) Barneby, poorly distinguished by a narrow, usually pedunculate spike. A similar pattern of variation separates D. compacta into a commoner, more western var. pubescens (Gray) Barneby, with spikes raised well beyond the linear foliage, from the rarer, more eastern var. compacta in which the ampler leaves are developed the length of the stem and are associated with longer stipules and longtailed interfloral bracts. — Inflorescences and detached cauline leaves × 1; the rest × 5. D. purpurea var. purpurea: 1) top of stem of tall virgate type, with detached leaves of dwarf western forms, one densely gray-silky; 2) bracts, ventral view; 3) flower; 4) calyx with externally glabrescent teeth, a variant common in Missouri; 5) calyx, laid open; 6) petals, all from different plants, the banners in ventral view; 7) androecium, from abaxial side. D. purpurea var. arenicola: la) spike at early anthesis. D. compacta var. pubescens: 1) top of stem; 2) flower + bract, with same bract in dorsal view; 3) calyx, laid open; 4) fruiting calyx; 5) pod, profile and vertical views. D. compacta var. compacta: 6) top of stem; 7) flower + bract; 8) petals.
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Taxonomy
Dalea purpurea var. arenicola (Wemple) Barneby
Dalea purpurea Vent. var. purpurea
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Copyright Statement
Copyright The New York Botanical Garden Press
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License Statement
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Cite This Image
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Image Type