FLORA OF THE DISTRICT OF COLUMBIA. 35 



Ovary 1; fruit a single capsule or drupe. 



Corolla about as long as the calyx; fruit indehiscent, ;i-seeded, purplish or 



yellowish; leaves often clasping the stem Triosteum (p. 260), 



Corolla much longer than the calyx; fruit dehiscent, not colored, usually 

 wilh more than 3 seeds; leaves not clasping. 

 Capsule abruptly contracted at the l)ase; seeds on hooks inside the capsule; 

 sitamens fewer than the corolla lobes. Flowers bluish or purjilish. 



Ruellia (p. 256). 

 Capsule not contracted at the base; seeds not on hooks; stamens as many 

 as the corolla lobes. 

 Stamens opposite the corolla lobes; flowers bright yellow or else solitary 

 in the axils. Corolla tube none or scai'cely any. 



PRIMULACEAE (p. 225). 

 Stamens alternate with the corolla lobes; flowers never bright yellow 

 nor solitary in the axils. 

 Capsule 1-celled; seeds numerous; plants glabrous or nearly so; leaves 

 sometimes reduced to scales; corolla tube sometimes nearly obso- 

 lete, usually thick and stout GENTIANACEAE (p. 228). 



Capsule 3-celled; seeds 3; plants usually pubescent; leaves never 

 reduced to scales; corolla tube long and slender... Phlox (p. 235), 



AA. COROLLA OP DISTINCT PETALS OR WANTING (tSE CALYX SOMETIMES COROLLA-LIKE), 



Leaves dotted with black glands, usually sessile. Flowers yellow or pink; leaves 



mostly sessile HYPERICACEAE (p. 204), 



Leaves not dotted with black glands. 



Leaves with stipules. 



Leaves obovate; petals 2 or 3, evident; plants of very wet soil. 



ELATINACEAE (p. 205). 



Leaves linear; petals 5, or very minute or wanting; plants of dry soil. 



Petals about 3 mm. long; pedicels glandular-pubescent Tissa (p. 151). 



Petals minute or none; pedicels without glandular pubescence. 



CORRIGIOLACEAE (p. 150), 

 Leaves without stipules. 



Plants with milky juice; capsule deeply 3-lobed. Upper leaves usually whorled; 



flowers small, white or greenish EUPHORBIACEAE (p. 194). 



Plants with colorless juice; fruit not 3-lobed. 

 Stems 1-flowered, the flowers solitary on long slender peduncles, nodding; 

 sepals 4, petal-like, thick and leathery, large (2.5 cm. long). Leaves sessile 



or nearly so, silky beneath Vioma (p. 160). 



Stems usually with more than 1 flower, the flowers not solitary on long slender 

 peduncles, not nodding; sepals smaller, not thick and leathery. 

 Flowers in simple spikes or racemes, very irregular, the sepals 5, 3 of them 

 small, 2 of them large and colored like the 3 petals. Leaves often whorled ; 



fruit very flat POLYGALACEAE (p. 193), 



Flowers not in simple spikes or racemes, not irregular. 

 Leaves mostly whorled in 3's, very fleshy, obovate; branches of the inflo- 

 rescence 1-sided. Petals white Sedum (p. 171), 



Leaves not whorled, or, if so, the blades not fleshy; branches of the inflo- 

 rescence not very 1-sided. 

 Calyx and corolla wanting; fruit 4-lobed. Flowers solitary in the axils; 

 leaves obovate; small prostrate plants of wet soil. 



CALLITRICHACEAE (p. 197), 

 Calyx and usually a corolla present; fruit not 4-lobed b, bb. 



