ROSACEJE 549 



diameter; calyx prominent, with long slender spreading and reflexed coarsely serrate usu- 

 ally persistent lobes villose on the upper surface; flesh thin, yellow, rather dry; nutlets 

 4 or o, acute at the ends, prominently ridged on the back with a broad deeply grooved ridge, 

 generally furnished with obscure ventral depressions, about \' long. 



A tree, sometimes 30 high, with a short trunk frequently 1 in diameter, covered with 

 dark scaly bark, stout ascending branches forming a narrow open irregular head, and slen- 



der nearly straight glabrous branchlets dark orange-green when they first appear, becoming 

 light chestnut-brown, lustrous and marked by pale lenticels in their first season, and armed 

 with stout straight or slightly curved bright chestnut-brown shining spines l^'-2' in length, 

 long persistent and becoming branched on old stems. 



Distribution. Fence rows, southwest of the village of Weston, near Toronto, Ontario. 



8. COWANIA D. Don. 



Trees or shrubs with scaly bark and rigid terete branchlets. Leaves alternate, simple, 

 lobed or rarely linear, subcoriaceous, straight- veined, glandular-dotted on the upper sur- 

 face, tardily deciduous or persistent, short-petiolate; stipules adnate to the base of the 

 petiole. Flowers solitary at the end of short lateral branches; calyx-tube turbinate, per- 

 sistent, the limb 5-lobed, deciduous, the lobes imbricated in the bud; disk thin, adnate to 

 the tube of the calyx, its margins thickened; petals 5, obovate, spreading, larger than the 

 calyx-lobes; stamens numerous, inserted in two rows in the mouth of the calyx-tube, in- 

 curved, persistent; anthers peltate, eglandular, 2-celled, opening longitudinally; carpels 

 5-12, inserted in the bottom of the calyx-tube, free, villose, 1-celled; style short, villose, 

 stigma simple, filiform; ovule solitary, ascending: raphe linear, dorsal; micropyle inferior. 

 Fruit composed of 5-12 1-celled ellipsoidal akenes, included in the tube of the calyx, and 

 tipped with the much elongated persistent styles covered with long white hairs; seed filling 

 the cavity of the carpel, linear-obovoid, erect; hilum basal, minute; testa membranaceous; 

 albumen thin; cotyledons obteng, radicle inferior. 



Cowania is confined to the dry interior region of the United States and Mexico. Three 

 species can be distinguished; of these the type of the genus, Cowania mexicana D. Don, 

 sometimes attains the size and habit of a small tree. The genus was named in honor of 

 James Cowan (died 1823), an English merchant who traveled in Mexico and Peru and sent 

 plants to England. 



1. Cowania mexicana D. Don. 



Cowania Stansburiana Torr. 

 Cowania Davidsonii Rydb. 



Leaves short-petioled, cuneate, re volute on the margins, 3 or rarely 5-lobed above the 

 middle, the lobes linear, entire or slightly divided, coriaceous, dark green above, hoary- 



