ROSACEAE. 



119 



COWANIA. 



(Family Rosaceae). 



Shrubs: evergreen. Twigs ter- 

 ete, slender, from brown becom- 

 (/^\ ing gray with scurfy outer cortex: 



nil ^ r ^^ pith minute, round. Buds soli- 

 ' f(^y I ^xJy tary, sessile, at first ovoid with 2 



liVfr^s. outer scales but rather quickly de- 



veloping short branches sheathed 

 by overlapping leaf-bases. Leaf- 

 scars alternate, half-round, min- 

 ute, much raised on thin winged 

 bases topped by the rather per- 

 sistent stipules: bundle-trace 1, 

 indistinct. Leaves as in Fallugia 

 but very glandular-warty, or in 

 one species (C. ericaefolia) min- 

 ute, entire, and pungent. 



Cowania, Fallugia, and Purshia 

 are three genera with rather simi- 

 lar leaves. As in Potentilla, these 

 disarticulate from the top of a 

 dilated persistent base correspond- 

 ing to the lower part of the petiole with stipules attached 

 to its sides. Leaf-bases of this sort, which are found in a 

 number of Rosaceae, are more frequent in the related family 

 Leguminosae, and transitions may be found between extreme 

 cases like these and the less produced but otherwise com- 

 parable leaf-cushion found in the greater number of rosaceous 

 and leguminous genera. 

 Twigs from bristly and puberulent glabrescent. 



C. Stansburiana. 



