268 



BRASSICACEAE 



4-5 dm. high, canescent with stellate hairs. Leaves 3-6 cm. long, lanceolate to oblanceolate, 

 narrowed at base to a short winged petiole, subentire or usually coarsely dentate or lobed, 

 stellate-canescent on both surfaces ; racemes terminating the numerous branchlets ; sepals oblong, 

 2.5 mm. long; petals 3 mm. long; fruiting pedicels 2-10 mm. long; pods ascending, terete, 

 12-16 mm. long, 0.5 mm. thick, irregularly torulose, with a slender elongated beak. 



Rock crevices, Sonoran Zones; White and Coso Mountains, Inyo County, California, to western Texas and 

 southern Arizona. Type locality: "Pass of the Limpia," Texas. June-Nov. 



17. *DESCURAINIA Webb & Berthel. Phytogr. Canar. 1 : 71. 1836. 



Annual, biennial or sometimes perennial herbs with finely dissected or coarsely bipin- 

 natifid leaves and pubescence of forked hairs often mixed with glandular hairs. Inflores- 

 cence racemose, flowers small, shades of yellow, sometimes tinged with rose. Petals 

 clawed, obovate, obtuse. Sepals obtuse, erect. Stamens 6, sometimes longer than petals 

 and sepals. Pistil cylindric; style short, thick; stigma simple, depressed-capitate. Fruiting 

 pedicels slender; siliques cylindric or claviform, septum 1-3-nerved. Seeds in one or 

 two rows, minute, oblong or ellipsoid, reticulate. [Name in honor of Francis Descurain, 

 friend of Antoine and Bernard Jussieu.] 



About 20 species occurring most abundantly in the cold and temperate regions of North and South America 

 while a few species are found in Europe, Asia, and the island groups of West Africa. Type species, Descnrainia 

 Sophia (L.) Webb. 



Upper as well as lower leaves 2-3-pinnate; siliques 15-30 mm. long, septum of silique with 2-3 longitudinal 



nerves. 1. D. Sophia. 



Upper leaves pinnate, the divisions often incised; siliques mostly less than IS mm. long (see D. obtusa adeno- 

 phora), septum of silique with 1 longitudinal nerve. 

 Siliques linear. 



Siliques with 2-28 seeds; seeds distinctly in one row; style conspicuous. 



Siliques 7-15 mm. long, 8— 28-seeded. 2. D. Richardsonii viscosa. 



Siliques 3-6 mm. long (rarely 7), 2-6-seeded. 3. D. californica. 



Siliques with 40-60 seeds; seeds in two rows sometimes appearing one from crowding; style obsolete 

 or nearly so. 4. D. obtusa adenophora. 



Siliques clavate; seeds in two rows; style obsolete or nearly so. 



Siliques 5-12 mm. long; seeds 12-20. 5. D. pinnata californica. 



Siliques 2-4 mm. long; seeds 2-4. 6. D. paradisa. 



1. Descurainia Sophia (L.) Webb. Flixweed, Tansy-mustard. Fig. 2001. 



Sisymbrium Sophia L. Sp. PI. 659. 1753. 



Sisymbrium parviflorum Lam. Fl. Franc. 2: 519. 1778. 



Descurainia Sophia Webb ex Prantl in Engler & Prantl, Pflanzenf. 3. abt. 2: 192. 1892. 



Sophia Sophia Britt. in Britt. & Brown, 111. Fl. 2: 144. 1897. 



Sophia parviflora Standley, Contr. U.S. Nat. Herb. 22: 347. 1921. 



Annual leafy herb branching above the base, 2.5-4 dm. high. Leaves hoary-canescent to 

 green and glabrate, not glandular, twice or thrice pinnate into many narrowly linear to linear- 

 oblong segments ; flowers small, pale greenish yellow or yellowish white ; sepals 2 mm. long ; 

 petals 1.5 mm. long; stamens surpassing all other floral parts; pedicels ascending, 9-11 mm. 



*Text of the genus Descurainia contributed by Roxana Stinchfield Ferris. 



1994 

 1994. Cochlearia officinalis 



1995 

 1995. Sisymbrium officinale 



1996 

 1996. Sisymbrium altissimum 



