MUSTARD FAMILY 287 
l. D. verna, L. (Fig. 7, pl. 56.) VERNAL WHITLow Grass. A low 
spreading plant, 1 to 5 in. high, with stems naked from the rosette to 
the flowers or fruit. Leaves of the basal rosette elliptic, numerous, 
hairy. Flowers small on foot-stalks $ to 1 in. long. Fruit an oval or 
oblong pod. Common in sandy places. Feb.-May. 
2./D. caroliniana, Walt. (Fig. 5, pl. 56.) CaroLInAa WHITLOW 
Grass. Plant about the size of the last. One or two pairs of leaves 
extending upon the flower stem. Pods 1/3 to 2/3 in. long. March-June. 
3. D. incana, L. (Fig. 6, pl. 56.) Twistep WHITLOW GRASS. 
Leaves long, lance-shaped or with the apex broadest, remotely toothed 
with rather conspicuous teeth. Small leaves extending up the flower 
stem arranged alternately. In the Green Mountains and Adirondacks. 
23. ARABIS, L 
Plants usually rather small; hairy or smooth. Pods long and slender, 
flattened. Flowers white or purple. 
Basal leaves! mot inayrosette . 2 3 ss is = a) a POtens 
Basal leaves in a rosette. 
Leaves of rosette lyre- fopned 
Pods erect). 1. ool vated): Tob uve rieme chute UrcMaieu ce NA ERT CEO 
Pods drooping . A. canadensis 
Leaves of rosette narrow “elliptic, deeply ‘or “not deeply dentate, 
Plante vieryowhatty,. icine). leukten teiaatc hom erarmnon nner as A. hirsuta 
Plant not very hairy . oA: brachycarpa 
Leaves of rosette long, narrow and deeply toothed or cut by broad and 
deep sinuses ce oO GM USS ilten ol zle gate 
Leaves of rosette ege- shaped, dentate. 
Upper stem leaves with entire margins . . . . . . A. laevigata 
Upper ‘stem leaves) markedly, dentate) 3.) (5°) 2). 3 45 dentata 
12 A. lyrata, L. (Fig. 8, pl. 55.) Lyrt-LEAvED Rock-cress. Slen- 
der plants, in tufts, 4 to 12 in. high, Smooth or sometimes somewhat 
hairy below. Basal leaves feather formed, upper narrow, with entire 
margins and blunt apex.. Flowers few in a terminal cluster, white. 
Pods long and very slender. Sandy places and rocky precipices. April- 
Sept. 
2. A. patens, Sulliv. Spreapine Rocxk-cress. Plant downy, 1 to 2 
ft. high. Leaves alternate on the stem, without leaf-stalks and to some 
extent auricled, the margins sharply toothed or nearly smooth. Flowers 
white; pods an inch or more long. Eastern Penna., westward. Summer. 
3. A. canadensis, L. SickLEe-pop. Stem not branching, 1 to 3 ft. 
high; smooth or with soft hairs below. Basal leaves deeply dentate or 
feather-formed, stem leaves, the lower rather broadly lance-shaped with 
dentate margins, the upper ones narrow lance-shaped with entire margins. 
Pods long and drooping. Flowers greenish-white. Woods. June-Aug. 
4. A. hirsuta, (L.) Scop. (Fig. 9, pl. 55.) Hatry Rock-cress. 
Stem scarcely branching, 1 to 2 ft. high; leaves of rosette deeply den- 
tate or more or less lyrate. Stem leaves narrow lance-shaped, clasping 
the stem, Whole plant quite hairy. Flowers greenish-white. Pods long 
and slender. Sandy and rocky places. May-Sept. 
5. A. brachycarpa, (T. and G.) Britton. Purrre Rock-cress. 
Stem branched, 1 to 3 ft. high, smooth except at lower part. Basal 
