SAXIFRAGE FAMILY 357 



seeded, dehiscing along or between the beaks. Seeds small, the testa roughened or smooth. 

 [Name Latin, meaning stone-breaking, said by some to refer to the fact that many of 

 the species grow in rock-clefts, by others to the supposition that certain species would 

 cure stone in the bladder.] 



About 250 species, many circumboreal and nearly all restricted to the north temperate zone. Besides the 

 following, about 40 species occur in the more easterly and northerly parts of North America. Type species, 

 Saxifraga granulata L. 



Hypanthium turbinate to campanulate, well developed in mature flowers, ultimately longer than the sepals; flower- 

 ing stems leaf-bearing. 

 Petals deciduous, not reflexed, the claw, if present, very short and broad. 



Plants without caudex, producing only annual flowering stems from a slender rootstock. 



All but the relatively large terminal flower regularly replaced by conspicuous bulblets; plants more 

 or less glandular-pubescent. 1. S. cernua. 



Flowers not replaced by bulblets; plants almost or quite glabrous. 



Sepals acuminate to merely acute; cauline leaves longer than wide, sharply 3-lobed at the apex. 



2. S. Nuttallii. 



Sepals obtuse; at least the lower cauline leaves wider than long, crenately lobed. 



3. 6". debilis. 



Plants with perennial leafy caudices, often with offsets, the flowering stems sharply differentiated from 

 the basal portions of the plants. 



Leaves spatulate to flabellate, digitately cleft at the apex; petals S— 7 mm. long. 



4. 6". caespitosa. 



Leaves entire, a few of the larger cauline with a pair of shallow teeth toward the apex; petals 

 3-5 mm. long. 5. .S". adscendens oregonensis. 



Petals withering-persistent, distinctly and narrowly clawed, reflexed at maturity; leaf-blades broadly cuneate, 

 finally disarticulating from the petiole. 6. 5". fragarioides. 



Hypanthium shallow, only slightly developed, remaining relatively shallow even in fruit. 



Leaves opposite, densely imbricated and decussately 4-ranked on the sterile branches and flowering stalks; 

 petals purple, fading to lilac; densely matted perennial. 7. 6". oppositifolia. 



Leaves alternate or basal; petals white or yellow. 



Leaf -blades fan-shaped to obovate-cuneate, sharply dentate except at the base; the petioles dilated above; 

 primary branches of the inflorescence ultimately elongated and ascending. 



8. 5". Lya//j't. 

 Leaf-blades orbicular or reniform to oblong or lanceolate, never fan-shaped or obovate-cuneate; petioles 

 not markedly dilated above. 

 Blades of the leaves at least as broad as long, reniform to orbicular, more or less cordate to truncate 

 at the base. 

 Leaves orbicular to reniform-orbicular, more or less sharply dentate; petals white; filaments 

 petaloid; relatively robust perennials. 



Leaves without stipules, simply and almost evenly dentate with roundish gland-tipped 

 teeth; scapes from a slender horizontal rhizome. 



Petals suborbicular to elliptic-obovate, with abrupt and slender claws; inflorescence 

 elongate, widely paniculate-cymose. 9. S. arguta. 



Petals elliptic-oblong to ovate, gradually narrowed into short relatively stout claws; 

 inflorescence short, closely corymbose. 10. 5. aestivalis. 



Leaves with stipular dilations at the base of the petioles, the blades of at least the larger 

 leaves with the main teeth in turn 3-dentate; scapes from an erect bulb-like rootstock. 



11. 5". Mertensiana. 

 Leaves, particularly the basal, truly reniform (much broader than long), not at all orbicular, 

 shallowly and crenately 3-5-lobed; petals yellow; filaments subulate, not petaloid; very 

 delicate annual or biennial. 12. .S". Sibthorpii. 



Blades of the leaves longer than broad. 



Caudices producing more or less horizontal perennial branches, these densely beset with small 

 leaves; plants suffrutescent at the base. 



Leaves thickish, fleshy, semi-terete, often slightly revolute, eciliate; petals uniformly white; 

 filaments petaloid, broadened above. 13. S. Tolmiei. 



Leaves relatively thin, parchment-like, spinulose-ciliate and cuspidate; petals veined and 

 often spotted with maroon; filaments subulate. 14. 5". bronchialis austromontana. 



Caudices not producing horizontal perennial branches; plants herbaceous throughout. 



Petals mostly dissimilar, 3 of them broader than the other 2; floral bulblets often present. 

 Plants (the caudex) perennial; scapes 1-4 dm. high; leaves spatulate, sharply toothed 

 above the middle; pedicels at least not consistently or strikingly deflexed, the lateral 

 often bulblet-bearing. 15. S. ferruginea. 



Plants annual; scapes 0.5-2 dm. high; leaves linear-elliptic to oblong-oblanceolate, 

 mostly entire; pedicels soon deflexed, all but the terminal bulblet-bearing. 



16. 5". bryophora. 



Petals essentially alike; floral bulblets not present; plants from a perennial caudex. 



Petals net markedly longer, or very often shorter, than the sepals; inflorescences often 

 head-like or umbel-like. 



All the petals slightly and consistently longer than the sepals; scapes essentially 

 and peduncles and pedicels wholly glabrous and non-glandular; inflores- 

 cence aggregated into a head-like or umbel-like cyme. 



17. S. aprica. 



Petals varying from slightly shorter to slightly longer than the sepals; scapes and 

 peduncles (and often the pedicels) glandular-pubescent and -puberulent. 



Longest petals about equaling the sepals; congested cy mules approximate in 

 a narrowly pyramidal cyme. 18. S. Columbiana. 



Longest petals slightly longer than the sepals; cymules congested, the lower 

 at anthesis separated from the others by the elongation of the peduncles. 



19. S. nidifica. 



Petals markedly longer than the sepals, conspicuous; inflorescences not head-like or 

 umbel-like; scapes and peduncles mainly glandular-pubescent. 



Cymules more or less compact at maturity, in narrowly pyramidal or corymb-like 

 clusters. 

 Leaves gradually narrowed to the base, almost or usually quite without peti- 

 oles; robust plants, mostly 4—8 dm. tall. 



20. .S". oregana. 



