DECANDRIA. DIGYNIA. 285 



An American genus, if we exclude H. horfensisof India, 

 separated principally on tlie ground of its producing 3 

 styles, which is perhaps occasionally common to every 

 Bi/drantii'ea. 



405. SAXIFRAGA. L. (Saxifrage.) 



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

 sule 1 -celled, many-seeded, opening betwixt 

 the 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. Aizoon. 2. stellaris. 3. serpyllifolia. 4. 

 Androsacea. 5. broncJualis. 6. nivalis. 7- virginica. 8. Geum. 

 ^. leucanthemifoUa. \Q. pensijlvunica. \\. erosa. Ph. Pa- 

 nicle slender and divaricately branched, by which it is 

 readily distinguished from No'.lO. 12. oppositifoUa. PUow- 

 ers bright purple. 13. aizoides. 1^. setigera. iS.rivula- 

 ris. 16. sibirica. 17. pectinata. 18. ccespitosa. 19. tri- 

 cuspidata. Note. All these species, except Nos. 7, 9, 10, 

 11, are indigenous to lower Canada, Labrador, or the 

 colder regions of New Califonia. The whoie 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, S-valvedj one of 

 the valves larger. 



Leaves mostly radical, simple, or ternately divided, 

 scapes or stems racemose or paniculate. 



Species. 1. T. cordifoUa. 2. Meiiziesii. 3. trifoUata. 

 4. bitemata. 



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

 also indigenous to Northern Asia. 



40r. MITELLA. L, 



Calix 5-clet't, 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. 



