Spring Flora of Oklahoma 
55 
Cotyledons accumbent; petals generally present. 
2. L. virginicum. 
Cotyledons incumbent; petals minute or wanting. 
3. L. densiflorum. 
Pods oblong, winged all round, longer than wide, about 
2" high. 4. L. sativum. 
1. Lepidium Draba L. Hoary Cress. Perennial, hoary-pubes¬ 
cent, branched at the inflorescence. Leaves oblong or lanceolate- 
oblong, obtuse, slightly dentate or entire, the lower petioled, the up¬ 
per sessile and clasping. Flowers white, l"-2" broad. Pods very 
broadly ovate, or cordate, arranged in short corymbose racemes. 
Waste places. April-June, Oklahoma County. 
2. Lepidium virginicum L. Wild Pepper-grass. Basal leaves 
obovate or spatulate in outline, generally with a large terminal lobe 
and numerous, small, lateral ones, all dentate, glabrous or slightly 
pubescent. Stem-leaves lanceolate or oblong-linear, sharply dentate 
or entire, sessile, or the lower stalked. Flowers white, Stamens 2. 
Pods flat, short-oval or orbicular, minutely winged above. 
In fields and along roadsides. May-November. 
3. Lipidium densiflorum Schrad. Wild Pepper-grass. Basal 
leaves pinnately-lobed or pinnatifid. Pods obovate-orbicular to ovate, 
slightly wing-margined above. 
In dry soil. May-August. Common. 
4. Lepidium sativum L. Garden Pepper-grass. Annual, glabrous, 
usually much branched. Lower leaves 2,-pinnate, or pinnate with the 
segments lobed, or pinnatifid, the lobes entire or incised. Stamens G. 
Silicles ovate-oval, emarginate, winged all round. 
In waste places. May to August. Common. 
VIII. THLASPI (Tourn) L. 
Erect, glabrous, annual or perennial herbs, with entire 
or dentate leaves, the basal ones forming a rosette, those 
of the stem or at least the upper ones, auriculate or clasp¬ 
ing. Flowers white or purplish. Pod obcuneate, obcordate 
or oblong-orbicular, flattened at right angles to the narrow 
partition, crested or winged. Valves dehiscent. Seeds 2 
or several in each cell, wingless. 
1. Thlaspi arvenis© L. Field Penny-cress. Annual, glabrous, 
simple or branching above. Basal leaves petioled, oblanceolate, early 
deciduous. Stem-leaves oblong or lanceolate, sparingly dentate, the 
upper clasping by an auricled base, the lower merely sessile. Flowers 
