FLORA OF THE DISTRICT OF COLUMBIA. 41 



Corolla regular or nearly bo, none of the petals spurred. 

 Leaves very thick and succulent. Petals pink or purple; fruit of 



several many-seeded follicles - - - Sedum (p. 171) . 



Leaves thin, never fleshy. 

 Sepals and petals each 4. Fruit a 1 or 2-celled pod, usually much 

 longer than wide; stipules none; flowers mostly in racemes. 



BRASSICACEAE (p. 163). 



Sepals or calyx lobes and petals each 5. 



Sepals distinct; fruit of numerous achenes. Petals yellow. 



Ranunculus (p. 158). 



Sepals united, at least below; fruit not of achenes. 

 Leaves mostly basal, hairy, the blades rounded, cordate at the 

 base; fruit a 1-celled capsule. Flowers in racemes. 



Heuchera (p. 171). 

 Leaves mostly borne on the stems; fruit not a 1-celled capsule. 

 Stipules none; flowers in 1-sided spikes; plants glabrous. 



PENTHORACEAE (p. 171). 



Stipules present; flowers never in 1-sided spikes; plants 



usually pubescent MALVACEAE (p. 202). 



KEY TO THE FAMILIES BASED MADNLY ON FLORAL CHARACTERS. 



Division I. PTERIDOPHYTA. Ferns and fern allies. 



Plants without true flowers, reproducing by spores (no embryo being formed); 

 fernlike, mosslike, or rushlike plants. 



Plants aquatic, inhabiting rock pools and tidal shores: leaves rushlike, tufted 

 upon a very short trunk; sporangia borne within the hollow leaf bases. 



ISOETACEAE (p. 60). 



Plants terrestrial; leaves not ruahlike; sporangia not borne within hollow leaf bases. 

 Stems hollow, jointed, grooved, rough; leaves reduced to toothed sheaths surround- 



ingthe joints EQUISETACEAE (p. 58). 



Stems not hollow, jointed, grooved, or rough; leaves minute to very large, never 

 reduced to sheaths upon the stem. 

 Leaves minute (1 cm. long or less) and exceedingly numerous, sessile, awllike or 

 bractlike, 4-many-ranked ; plants more or less mosslike. 

 Plants depressed or short-creeping, not over 3 or 4 cm. high; spores of 2 kinds, 



megaspores and microspores SELAGDNELLACEAE (p. 60). 



Plants mostly wide-creeping, the simple erect peduncles or bushy aerial branches 

 10-30 cm. high; spores of one kind, very minute. 



LYCOPODIACEAE (p. 59). 



Leaves very much larger, few, not awllike or bractlike, stalked, fascicled or 

 obscurely 2-ranked; plants not mosslike. 

 Plants vinelike, twining; pinnae palmate ly 4-7-lobed, borne alternately in pairs. 



SCHIZAEACEAE (p. 53). 

 Plants not vinelike or twining; pinnse not palmately lobed or borne in pairs. 

 Sporangia large, sessile, borne in a s'alked terminal spike or loose panicle, 

 the sterile blade appearing lateral, simple and entire or several times 



pinnately divided OPHIOGLOSSACEAE (p. 52). 



Sporangia small, stalked, borne in clusters (sori) on the back of ordinary 

 foliage leaves or modified parts of these, or wholly concealed within the 

 hard berry-like or podlike divisions of greatly modified, wholly fertile 

 leaves. 



