DECANDRI4. DIGYNIA. 285 



An American genus, if we exclude H. hortensis of Jndi&t 

 separated principally on the ground of its producing 3 

 styles, which is perhaps occasionally common to every 



405. SAXIFRAGA. L, (Saxifrage.) 



Calix 5-parte(l, persistent. Petals 5. Cap- 

 sule 1 -celled, raany-seetied, opening betwixt 

 ilie persistent styles. 



Leaves alternate, rarely opposite, entire or divided; 

 sometimes all radical; flowers mostly numerous, densely 

 or loosely paniculate, in some species nearly solitary. 



Species. 1. S. »4/?oo/i. 2. siellaris. Z. serpyllifolia. 4. 

 fjidrosacea. 5. bronchialis. 6. nivalis. 7- virginica. 8. Geuin, 

 S- leucanthemifoHa. \0. pensylvanica. \\. erosa. Ph. Pa- 

 nicle slender and divaricately branched, by which it is 

 readily distinguished from No. 10. 12. oppositifoUa. Flow- 

 ers bright purple. 13. aizoides. I*, setigera. 15. rivula- 

 rls. 16. sibirica. 17. pectinata. 18. ctespitosa. 19. tri' 

 cuspidata. Note. x\11 these species, except Nos. 7, 9, 10, 

 11, are indigenous to lowe«r Canada, Labrador, or the 

 colder regions of New Califonia. The whole genus of 

 more than 70 species is chiefly alpine and European. 



406. TIARELLA. L. 



Calix 5-parted, persistent. Petals 5, entire, 

 inserted upon the calix and conspicuously un- 

 guiculate. Capsule 1 -celled, 2-valved^ one of 

 the valves larger. 



Leaves mostly radical, simple, or ternately divided, 

 scapes or stems racemose or paniculate. 



Species. 1. T. cGvdijlUa. 2- Menziesii. 3. trifoUata. 

 4. biternata. 



A North American genus, of which Nos. 1 and 3, arc 

 also indigenous to Northern Asia. 



40r. MITELLA. L. 



Calix 5-cleft, persistent. Petals 5, pinnati- 

 fid, inserted upon the calix. Capsule 1 -celled, 

 subsemibivalve; valves equal. 



Leaves simple, mostly radical; scapes naked or bifoli- 

 ate, 1 species produces a prostrate stem; flowers race- 

 mose or loosely spiked. 



