SAXIFKAGACEAE. 143 



1. H, americana L. Loaf -blades orbicular-ovate or suborbicular, 5-11 cm. 

 wide, the lobes broad and -with broad teeth: sepals much longer than the free 

 portion of the hypanthium: petals about 1.5 mm. long, spatulate, the blades 

 oblong or elliptic, finely toothed. — Common, on roadsides, and in woods and 

 thickets. 



2. H. Curtisii T. & G. Leaf -blades suborbicular, varying to ovate or reniform, 

 sometimes hispidulous above, and ciliate, the lobes broad and with few coarse 

 broad teeth: flowering branches glabrous below, puberulent above, leafy: 

 petals purple or pinkish, exceeding the sepals, the blades usually rhombic, 

 finely toothed : free portion of the mature hypanthium short. — S. Frequent 

 on rocky banks of the Susquehanna Eiver. — Schists. 



3. H. pubescens Pursh. Leaf -blades orbicular-ovate, glabrate in age, the lobes 

 often ovate, with usually sharply mucronate teeth: flowering branches densely 

 glandular-puberulent at least above: sepals together with the hypanthium 6-8 

 mm. long^ the lower ones ovate: petals purplish, the larger ones 2.5-3 mm. long, 

 the blades obovate, coarsely toothed: free portion of the mature hypanthium 

 long : stamens exserted. — S. Eare, on rocky islands and banks of the Sus- 

 quehanna Eiver. — Schists, 



3. MITELLA [Tourn.] L. Perennial herbs with lateral flowering branches. 

 Leaf-blades lobed and toothed. Flowers in racemes. Sepals equal. Petals 

 pectinately pinnatifid. Stamens 10: filaments very short. Styles very short. 

 Capsules abruptly narrowed near the apex. 



1. M. diphylla L. Plants 2-4 dm. tall: leaf -blades ovate to orbicular-ovate in 

 outline, 3-5-lobed, 3-8 cm. long: sepals ovate, 1-1.5 mm. long, acute: petals 

 2.5-3 mm. long: capsules 2-beaked at the apex, about 3 mm. long. — Eather 

 common, in rocky woods and on cliffs. — Spr. — Mitre-wort. Bishop 's-cap. 



4. CHRYSOSPLENIUM [Tourn.] L. Perennial (ours) semiaquatic herbs. 

 Leaf -blades crenate or lobed. Petals wanting. Stamens mostly 4-8. Styles 2. 

 Capsule flattened, 2-lobed, very short. 



1. C. americanum Schwein. Plants decumbent, 2-20 cm. long: leaf -blades 

 suborbicular to orbicular-reniform, 4-20 mm. broad: sepals 4, yellowish or 

 purplish within : fruit about 3 mm. long. — Common, in wet places and spring- 

 runs. — Spr. and sum. — Golden-saxifrage. Water-carpet. 



Family 5. HYDRANGrEACEAE. Hydrakgea Family. 



Shrubs or trees, or vines. Leaves mostly opposite : blades often 

 toothed. Flowers borne in raceme-like, corymb-like or panieled cymes. 

 Calyx of usually 4—10 sepals surmounting the often ribbed hypanthium. 

 Corolla of mostly 4^10 i3etals. Androeeium of 8-many stamens. Gynoe- 

 cium of 2-5, or rarely of 10, united carpels. Ovary wholly or partially 

 inferior. Fruit capsular. 



Stamens 8 or 10 : sepals minute, except in sterile flowers : petals valvate. 



1. Hydrangea. 

 Stamens 20-40 : sepals relatively large : petals convolute. 2. Philadelphus. 



1. HYDRANGEA [Gronov.] L. Shrubs. Leaf -blades toothed or lobed. 

 Sepals 4 or 5, minute, or petal-like in the marginal flowers. Petals valvate, 

 small. Stamens 8-10. Styles wanting or very short. Capsule opening between 

 the stigmas. 



1. H. arborescens L. Shrub with sparingly pubescent branches and twigs : 

 leaf -blades thin, ovate, oval, or elliptic: petals 1-1.5 mm. long: capsule-body 

 2-2.5 mm. long, broader than high. — Eather common, in rich rocky woods. — 

 Sum. — Hydrangea. 



