360 MISC. PUBLICATION 42 3, U. S. DEPT. OF AGRICULTURE 

 26. CAPSELLA. Shepherds-purse 



Plant annual; root leaves in a rosette, lyrate-pinnatifid, the stem 

 leaves dentate or entire, auricled at base; flowers in elongate racemes, 

 very small, the petals white; pods flat, wedge-shaped, dehiscent; seeds 

 numerous in each cell. 



1. Capsella bursa -pastoris (L.) Medik., Pflanzengatt. 1: 85. 1792. 



Thlaspi bursa-pastoris L., Sp. PL 647. 1753. 



Pinal and Maricopa Counties, a weed of waste land and lawns, 

 rare in Arizona. Extensively naturalized in North America from 

 Europe. 



27. CAMELINA. Falseflax 



Plant annual; stems erect, rather strict; leaves entire or denticulate, 

 the stem leaves auriculate-clasping ; flowers in elongate racemes, 

 small, the petals yellow; pods obovoid, turgid but somewhat com- 

 pressed ; seeds numerous in each cell. 



1. Camelina microcarpa Andrz. in DC, Regni Veg. Syst. 2: 517. 

 1821. 



Grand Canyon and Flagstaff (Coconino County), Chiricahua 

 Mountains (Cochise County), 7,000 to 8,000 feet. A weed of waste 

 ground introduced, in many parts of the United States, from Europe. 



An oil, somewhat similar to linseed oil, is obtained from the seeds. 



28. DRABA. 51 Whitlowgrass 

 Contributed by C. Leo Hitchcock 



Plants of diverse habit, annual, biennial, or perennial, with scapose 

 or leafy stems, usually pubescent with simple or forked hairs; leaf 

 blades entire or dentate; racemes short and corymbose to elongate; 

 petals white or yellow; pods 2-celled, dehiscent, strongly compressed 

 parallel to the partition and flat, or elongate and often twisted; seeds 

 numerous, in 2 rows in each cell. 



Key to the species 



1. Plants evidently perennial, the stems usually tall and leafy; petals yellow, 

 often fading to white, usually as much as 4 mm. long; style evident, 

 persistent; pods elongate, often twisted (2). 

 2. Plants scapose, the leaves in basal rosettes, grayish hirsute with stalked 



cruciform hairs; pods densely pubescent 1. D. asprella. 



2. Plants not truly scapose, some of the leaves cauline; pods often glabrous 

 (3). 

 3. Leaves mostly basal, narrowly oblanceolate, 1.5 to 8 cm. long, 2 to 7 mm. 

 wide, ciliate with simple or forked hairs; pods and upper portion of 



the stems glabrous; styles 1 to 1.5 mm. long 2. D. standleyi. 



3. Leaves usually rather uniformly pubescent, many of them cauline; stems 

 mostly pubescent throughout (4). 

 4. Styles less than 1.5 mm. long; pedicels strongly ascending to erect in 



"fruit 3. D. aurea. 



4. Styles 1.5 mm. long or longer; pedicels spreading or but slightly as- 

 cending (5). 

 5. Basal leaves oblanceolate, 3 to 8 cm. long, their bases matted on 

 the caudices; pubescence raiher sparse, hence all of the leaves 

 bright green 4. D. petrophila. 



si Reference: Hitchcock, C. Leo. a revision of the drabas of western north America. Wash. 

 Univ. Pubs. Biol. 11: 1-132. 1941. 



