SAXIFRAGACEAE (SAXIFRAGE FAMILY ) 447 



12. S. Oppositif61ia L. (MOUNTAIN S.) Leaves (2-4 mm. long) fleshy, ovate, 

 keeled, ciliate, imbricated on the sterile branches; petals purple, much longer 

 than the 5-cleft calyx. Calcareous rocks, Arctic Am., s. to Gulf of St. Law- 

 rence, mts. of n. Vt., Mont, and Ida. May, June, rarely Aug. (Eurasia.) 



5. TIARELLA L. FALSE MITERWORT 



Calyx bell-shaped, 5-parted. Petals 5, with claws. Stamens long and slen- 

 der. Styles 2. Capsule membranaceous, 2-valved ; the valves unequal. Seeds 

 few, at the base of each parietal placenta, globular, smooth. Perennials ; flow- 

 ers white. (Name a diminutive from rtdpa, a tiara, or turban, from the form 

 of the pistil, which is like that of Mitella, to which the name of Miterwort 

 properly belongs.) 



1. T. cordifblia L. Leaves from the rootstock or summer runners, heart- 

 shaped, sharply lobed and toothed, sparsely hairy above, downy beneath ; stem 

 (1-4 dm. high) leafless or rarely with 1 or 2 leaves ; raceme simple ; petals ob- 

 long, often subserrate. Rich rocky woods, N. S. and N. B. to Minn., Ind., and 

 southw. in the mts. Apr.-June. 



6. HEUCHERA L. ALUM ROOT 



Calyx 5-cleft. Petals 5, spatulate. Styles 2, slender. Capsule 1-celled, 

 with 2 parietal many-seeded placentae, 2-beaked, opening between the beaks. 

 Seeds oval, with a rough and close seed-coat. Perennials, with the round 

 heart-shaped leaves principally from the rootstock ; those on the stems, if any, 

 alternate. Petioles with dilated margins or adherent stipules at their base. 

 Flowers in small clusters borne in a narrow panicle, greenish or purplish. 

 (Named for J. H. Heucher, a German botanist of the 17th and 18th centuries.) 



Calyx regular or essentially so. 

 Calyx in anthesis 1.5-2 mm. long. 

 Leaves with prominent triangular lobes. 

 Lower leaf-surfaces glabrous or merely villous along the nerves . . 1. IT. mllosa. 



Lower leaf-surfaces villous 2. H. macrorhiea. 



Leaves reniform, with obscure rounded lobes 8. H. 'parviflora. 



Calyx in anthesis 3-6 mm. long 4. H. americana. 



Calyx oblique, often very irregular. 

 Stamens about equaling or slightly exceeding the calyx-lobes. 



Petioles hairy 5. H. hispida. 



Petioles at most granular- or glandular-puberulent 6. H. pubescent. 



Stamens about twice as long as the calyx-lobes 7. //. hirouUcaulix. 



1. H. villbsa Michx. Rootstock elongate, 0.5-1 cm. in diameter ; stems slen- 

 der (1-3 mm. in diameter at base}, 2-9 dm. high, more or less villous with rusty 

 hairs, especially below ; leaves basal, thin, acutely 7-9-lobed, on slender rusty- 

 villous petioles ; bracts of the loose panicle linear ; calyx and pedicels some- 

 what glandular-hispid ; petals spatulate-linear, about as long as the exserted 

 stamens, soon twisted. (H. crinita Rydb.) Shallow soil on rocks, Md. to 

 111., s. to Ga. and Tenn. June-Aug. 



2. H. macrorhiza Small. Similar; rootstock stout, woody, 1.5-2 cm. in 

 diameter; stems stout (4-8 mm. in diameter at base}, sometimes leafy, 3-10 dm. 

 high, very densely villous with sordid hairs ; basal leaves thick, suborbicular, 

 densely pubescent beneath, sparingly so above, on stout rusty-villous petioles ; 

 bracts of the panicle oblong. Limestone cliffs and river-bluffs, Ky. and Tenn. 



3. H. parviflbra Bartl. Stems slender, 1.2-6 dm. high, glandular-hirsute 

 (rarely glabrate), as well as the petioles, etc.; leaves round-reniform, with 7-9 

 short and broad rounded lobes; flowers very small (2 mm. long}; petals linear- 

 spatulate, twice as long as the calyx-lobes ; fruit narrow. (H. Mugelii Shuttlw.) 

 Shaded cliffs, Va. to s. 111., Mo. and Ga. 



4. H. americana L. (COMMON A.) Stems (6-9 dm. high), etc., glandular 

 and more or less hirsute with short hairs; leaves roundish, with short rounded 

 lobes and crenate teeth ; calyx very broad, 4 mm. long, the spatulate petals 



ualing or slightly longer than its lobes. (H. lancipetala Rydb.) Rocky A 





