Dicotyledones. 53 



XII. DRABA. Whitlow Grass. 



Low tufted herbs, often with stellate pubescence. Flowers white or 

 yellow ; pods elliptic, oblong, or linear, flattened parellel with the par- 

 tition. Seeds several in 2 rows in each cell. Stems scapose or leafy. 



1. Draba > verna, L. (L., verna, a native.) VERNAL WHITLOW GRASS. 

 Flowers white ; petals deeply 2-cleft. I to 5 inches high ; flowering stems leafless. 

 Leaves tufted at the base, oblong or spatulate-oblanceolate, entire or only dentate, 

 beset with stiff, stellate hairs. Pods oblong or oval, smooth, shorter than the 

 pedicels. In fields and sandy waste places. 



2. Draba Caroliniana, Walt. CAROLINA WHITLOW GRASS. Flowers white ; 

 petals entire. Pods linear, longer than the ascending pedicels. Flowering stems 

 i to 5 inches high. Leaves obovate and entire, clustered at the base, or only a 

 short distance up the stem, beset with stellate pubescence. 



3. Draba cuneifolia, Nutt. (L., cuneus, wedge ; folium, leaf.) Flowers white ; 

 petals emarginate ; pods oblong-linear, minutely hairy, longer than the horizontal 

 pedicels. 4 to 8 inches high, branching and leafy below; leaves obovate, cuneate, 

 or the lowest spatulate, dentate toward the summit. In fields and grassy places. 



4. Draba brachycarpa, Nutt. (Gr., brachys, short; karpos, fruit.) SHORT- 

 FRUITED WHITLOW GRASS. Flowers yellow ; the oblong pods & to inch long. 

 Basal leaves \ to 5 inch long, ovate or obovate, stem leaves oblong and entire. 

 Dry hills and fields. 



ARABIS. RockCress. 



(Named from Arabia.) 



Flowers white or purple. Pods linear, elongated, and flattened par- 

 allel with the partition; valves mostly i-nerved. Seeds in i or 2 rows 

 in each cell, usually margined or winged. Leaves seldom divided. 



1. Arabis Ludoviciana, Meyer. Stems ascending from 5 to i foot high. Stem 

 leaves pinnatifid, oblong, and narrow. Flowers very small and white. Pods 

 linear, spreading, nearly i inch long; seeds as broad as the pod, and winged. In 

 open places. 



2. Arabis dentata, T. & G. TOOTHED ROCK CRESS. Petals greenish white, 

 hardly exceeding the calyx; pods narrowly linear, sometimes exceeding i inch' in 

 length. Seeds oblong, in i row in each cell. Stems sparingly branched, i to 2 

 feet high. Basal leaves obovate and dentate, on margined petioles; stem leaves 

 oblong or oblanceolate, dentate, sessile, base auricled and clasping. 



XIV. ALYSSUM. 



(Gr., a, without or depriving; lyssa, madness. Greek name of a plant supposed to have 



remedial value.) 



Flowers white (or sometimes yellow). Pods orbicular, flattened at 

 the margins parallel with the partition ; seeds only i or 2 in each cell. 



