'76 



CRUClFIRAIi. 



VUL. II. 



I. Arabidopsis Thaliana (L.J Britton. Mouse-ear 

 or Thalc-crcss. Wall-cress. Fig. 2063. 



Arabis Thaliana L. Sp. PI. 665. 1753. 

 Sisymbrium Thalianum Gay, Ann. Sci. Nat. 7 ; 



.399- 



1826. 



Stenophragma Thaliana Celak. OEster. Bot. Zeitsch. 27: 177. 

 iS77- 



Annual, stem slender, erect, i'-i6' high, freely branching, 

 more or less pubescent with short stiff hairs, especially 

 below. Basal leaves 1-2' long, obtuse, oblanceolate or 

 oblong, narrowed into a petiole, entire or slightly toothed; 

 stem-leaves smaller, sessile, acute or acutish, often entire; 

 pedicels very slender, spreading or ascending, 2"-4" long 

 in fruit: flowers about li" long; petals about twice the 

 length of the sepals; pods narrowly linear, 4"-lo" long, 

 acute, often curved upw^ard, glabrous. 



In sandy fields and rocky places, Massacusetts and southern 

 Ontario to Minnesota. Georgia, Missouri, Arkansas and Utah. 

 Very common eastward. Naturalized from Europe. Native 

 also of northern Asia. Turkey-pod. April-May. 



2. Arabidopsis novae-angliae ( Rydb. ) Britton. Low or Northern Rock-cress. 



Fig. 2064. 



Arabis pclraca Hook. Fl. Bor. Am. i; 4-, in part. 1829- 

 Not Lam. 



Sisymbrium humile Wats. & Coult. in A. Gray, Man. Ed. 6, 

 71. 1890. Not Meyer, 1831. 



Braya humilis Robinson, in Gray & Wats. Syn. Fl. i' : 141, 

 in part. 1895. 



Pilosella novae-angliae Rydb. Torreya 7: 158- I907- 



Perennial, erect, 4-10' high, branching below, spar- 

 ingly pubescent. Leaves spatulate, or oblanceolate, the 

 lower obtuse, I'-a' long, narrowed into a petiole, sharply 

 dentate or rarely entire, the upper smaller, narrower, 

 often acute; flowers white or pink, ii''-2" broad; pedi- 

 cels ascending or erect, 2"-3" long in fruit; pods nearly 

 terete, glabrous, narrow ly linear, 6"-io" long, i" wide ; 

 valves finely nerved; style i" long. 



In rocky places, Anticosti. Willoughby Mountain, Vt., 

 near Michipicoten Harbor, Lake Superior. July. 



31. BARBAREA R. Br. in Ait. Hort. Kew. Ed. 2, 4: 109. 1812. 



Erect glabrous biennial or perennial branching herbs, with angled stems, pinnatifid 

 leaves, and racemose yellow flowers. Stamens 6. Siliqne elongated, linear, 4-angled, the 

 valves keeled or ribbed. Style short. Stigma 2-lobed or nearly capitate. Seeds in i row- 

 in each cell, flat, oblong, marginless ; cotyledons accumbent. [Name from St. Barbara, to 

 whom the plant was anciently dedicated.] 



.\ genus of about 7 species, natives of the temperate zones. Besides the following, another 

 occurs in western North America. Type species : Barbarea vulgaris R. Br. 



Pods obtusely 4-angled. slender-pedicelled ; leaf-segments 1-4 pairs. 



Pods divergent or ascending. i. B. Barbarea. 



Pods erect, appressed. 2. B. siricla. 



Pods sharply 4-angled, stout-pedicelled ; leaf-segments 4-8 pairs. 3. B.vcrna. 



