198 



Descriptive Flora 



RUBIACEAE. Madder Family. 



Houstonia angustifolia Michx. Innocence. Bluets. 



Baby's Breath. 



Smooth, delicate and square-stemmed, forked and much 

 branched plants with narrow, opposite leaves, and innumerable 

 tiny, dainty, white or delicate lavender, 4-petalled flowers less 

 than 14" across. Leaves simple, opposite. Blades narrow, 1 to 

 iy 2 " long, entire, with margins often rolled back. Petals 4, 

 velvety within. Stamens 4, alternate with the petals. These 

 flowers are of unusual interest because of the dimorphic char- 

 acter of the stamens and pistils. In some flowers the stamens are 

 long and exceed the pistil. In others the pistil rises above the 

 stamens. Widespread. April and thruout the summer. 



Houstonia humifusa Gray. 



Low, tufted, repeatedly-forked, wiry, square-stemmed 

 plants, 4 to 8" high, with small, narrow leaves and very small, 4- 

 lobed, white flowers, sessile in the forks or in the axils of the 

 upper leaves. Leaves simple, opposite, linear, appressed, more 

 or less crowded, 14 to l 1 /^' long. Corolla 4-lobed, about 3/16" 

 across, heavily bearded in the throat. In sandy soil and crevices 

 of flat limestone rocks of dry creek beds. March to June. 



Cephalanthus occidentalis L. Button Bush. Button Willow. 



Shrub with conspicuous white or yellowish-white, globular 

 heads of very fragrant flowers about 1 inch in diameter and re- 

 sembling globular pin cushions. Leaves simple, opposite or in 

 whorls of 3, lanceolate or oblong, 2 to 9 inches long. May, June 

 and July. In ravines, on banks of streams, and frequently in the 

 middle of dry creeks beds. 



Crusea tricocoa (Torr. & Gray) Heller. 

 (Crusea allococoa A. Gray.) 



Low hairy plants with short stout branches spreading close 

 to the ground and simple, opposite leaves joined around the stem 

 by a fringe of about six narrow, pointed, almost hair-like stipules. 



