Piptocoma rufescens Cass.

• Title

  Piptocoma rufescens Cass.

• Authors

  Nathaniel Lord Britton, Frances W. Horne

• Scientific Name

  Piptocoma rufescens Cass.

• Description

  Flora Borinqueña Piptocoma rufescens Piptocoma Family Carduaceae Thistle Family Piptocoma rufescens Cassini, Bulletin par la Société Philomatique de Paris 1817: 10. 1817. A shrub, in Porto Rico growing locally on hillsides with underlying serpentine rocks, in the western districts, and, quite plentiful, in large colonies, on the hills at Cape San Juan, where no serpentine is found; it also inhabits Santo Domingo and the Virgin islands. The genus, established by the French botanist Cassini, is monotypic, one species only being known; the nearest relatives are species of Vernonia; the generic name is Greek, referring to features of the scaly pappus of the achenes. Neither Spanish nor English names have been recorded. Piptocoma rufescens (reddish), is a branched shrub, with densely scaly foliage, from 1 to 2.5 meters high, the branches nearly round, the twigs slightly angled. The alternate, untoothed, short-stalked leaves are oblong, or lance-shaped, blunt or short-pointed, from 5 to 8 centimeters long, about 2.5 centimeters wide, or narrower, the upper surface dark green, the under side whitish-velvety and strongly veined. The numerous small heads of tubular, blue or pinkish flowers form nearly flat clusters at the ends of branches; the bell-shaped involucres of the flower-heads are about 6 millimeters high, composed of several series of firm bracts, the outer ones shorter than the inner, and woolly; the corollas have slender tubes and narrow limbs, and the anthers are arrow-shaped. The fruits (achenes) are 5-angled, about 2 millimeters long, bearing a pappus of 2 series of yellowish scales about 5 millimeters long, the inner series falling away (whence the generic name), the outer series persistent.