Daleae Imagines page 598 plate III

  • Title

    Daleae Imagines page 598 plate III

  • Creator(s)

    R. C. Barneby

  • Publisher

    The New York Botanical Garden Press

  • Description

    PLATE III Psorothamnus spinosus (Gray) Barneby and Ps. kingii (Wats.) Barneby, taxonomically isolated species of western North American deserts, the former, the Smoke Tree, widespread over the Sonoran Desert from the s. margins of the Mohave to n.-w. Sonora and centr. Baja California, the latter local on dunes in the lower Humboldt River valley in n. Nevada. In both species the flowers are borne laterally to a thorn-tipped rachis, but in other respects they are wholly different. The Smoke Tree is a small tree at maturity, leafless or nearly so, with innumerable silvery-gray branchlets clothed in summer with vivid indigo flowers. Of all Amorpheae, Ps. spinosus is the only species with more than two ovules; note also the callosities at base of the banner-blade. By contrast Ps. kingii is a lowly herb with diffuse, zigzag stems arising singly from wide-creeping rhizomes. The developed leaflets are sharply mucronate, the raceme is reduced to 1-4 flowers, the petals are clear blue, opening June to August. — Flowering branchlets or stems × 1; the rest × 5. Ps. spinosus: 1) summit branchlets; 2) leaf; 3) bract, ventral and dorsal views; 4) flower; 5) flower with calyx cut away to show insertion of petals; 6) banner, ventral and profile views; 7) androecium; 8) ovary, dissected lengthwise. Ps. kingii: 1) flowering stem; 2) leaflets; 3) raceme + flower; 4) banner, ventral view; 5) wing (back) and keel-petal; 6) androecium; 7) pod (2-seeded); 8, 8a) seeds, profile and ventral views.

  • Taxonomy

    Psorothamnus spinosus (A.Gray) Barneby

    Psorothamnus kingii (S.Watson) Barneby

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    Copyright The New York Botanical Garden Press

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  • Image Type

    Illustration