SAXTFRAGACE.E. (SAXIFRAGE FAMILY.) 57 



4. TIARELLA, L. 



Distinguished by the minute, slender petals, long exserted stamens, and the very une- 

 qual horns of the 2-carpeled ovary. 



1. T. umroliata, Hook. Somewhat hairy; flowering stems 4 to 15 inches high, 1-3- 

 leaved; leaves thin, cordate, 3-5-lobed, crenate-toothed; flowers small, panicled. 



5. HEUCHERA, L. ALUM-ROOT. 



Calyx tube coherent with the lower half of the ovary. Petals small, entire, clawed. 

 Ovary more or less 2-beaked; the beaks tapering into either filiform long, or subulate 

 shorter styles. Herbs with small, dull-colored paniculate flowers. Scarious stipules 

 adnate or distinct. Leaves round -cordate, obtusely lobed, crenate-toothed. 



1. H. micraiitha, Dougl. Scape, or few leaved flowering stems, a foot or two 

 high; leaves 2 to 4 inches in diameter; calyx acute at the base, lobes erect; styles 

 Blender. 



2. H. pilosissima, Fisch. & Mey. Very villous-pubescent or hirsute, with viscid 

 hairs; calyx rounded or obtuse at the base, the broad, short lobes incurving, densely 

 hairy; styles short. 



6. FHILADELFHUS, L. MOCK ORANGE. 



Calyx adhering to the ovary nearly or quite to the summit, persistent. Petals 4 or 5, 

 large, obovate or roundish. Stamens 20 to 40. Styles 3 to 5, united at the base or 

 nearly to the top. Shrubs with opposite leaves and showy white flowers. 



1. P. Gordianus, Lindl. Six to twelve feet high; leaves ovate to oblong-ovate, 

 mostly coarsly-serrate, 2 to 4 inches long; flowers in loose clusters, which are leafy at the 

 base; petals frequently an inch long. 



7. WHIFFLEA, Torr. 



Calyx lobes thin, white or whitish. Petals ovate or oblong. Ovary 3 to 5-celled. 

 Styles distinct, subulate. Small, trailing or diffuse, ours half shrubby plants, with 

 opposite, short petioled, 3-ribbed leaves, no stipules and small white cymose-clustered 

 flowers; peduncles naked, terminal. 



1. W. modesta, Torr. Leaves membranaceous, ovate or oval, obtusely few-toothed 

 or entire, an inch or less long. Flower 2 lines long, clusters close-flowered, fragrant. 



8. RISES, L. 



Calyx tube adnate to the globose ovary and extended beyond it, the limb commonly 

 petaloid. Petals erect, mostly smaller than the calyx-lobes. Stamens alternate with 

 the petals. Berry crowned by the withered remains of the flower. Shrubs with 

 alternate palmately lobed leaves. 



