458 EXOGENOUS OR DICOTYLEDONOUS PLANTS. 



Group 2. Flowers perfect, or rarely polygamous, with a regular and often 

 petaloid calyx. Ovary free. Ovules solitary in each ovary or cell. Em- 

 bryo curved or coiled around mealy albumen, rarely in the axis or exal- 

 buminous. Chiefly herbs. 



Ovary several-celled, consisting of a whorl of several one-ovuled carpels. 



PHYTOLACCACEJE, p. 460. 

 Ovary one-celled, with a single ovule. 



Stipules none. Ovule campy lotropous or amphitropous. 



Calyx herbaceous. CHENOPODIACE.S:, p. 461. 



Calyx and bracts scarious. AMARANTACE^S, p. 462. 



Calyx corolline, the persistent base indurated. NYCTAGINACE.S:, p. 462. 

 Stipules sheathing (ochreae). Calyx corolline. Ovule orthotropous. 



POLYGONACEJE, p. 462. 



Group 3. Flowers perfect, polygamous or dioecious, not disposed in aments, 

 with a regular, and often petaloid calyx. Ovary one-celled, or rarely 

 two-celled, with one or few ovules in each cell : but the fruit one-celled 

 and one-seeded. Embryo not coiled around albumen. Trees or shrubs. 



* Style or stigma one. 

 Calyx free from the ovary, and not enveloping the fruit. 



Flowers polygamo-dioecious. Anth. opening by valves. LAURACEJS, p. 463. 

 Flowers perfect. Anthers opening longitudinally. THYMELACE^E, p. 464. 

 Calyx free, but baccate in fruit and inclosing the achenium. 



ELEAGNACEJE, p. 464. 

 Calyx adnate to the ovary. 



Ovules several, pendulous from a stipe-like placenta. SANTALACE.E, p. 465. 

 Ovule solitary, suspended. 



Parasitic shrubs. Ovule without integuments. LORANTHACE^E, p. 466. 



Trees. Fruit a drupe. NYSSACE.E, p. 465. 



* * Styles or stigmas two, divergent. ULMACE.S, p. 466. 



Group 4. Flowers perfect, entirely destitute of calyx as well as corolla. Em- 

 bryo minute, inclosed in the persistent embryo-sac at the apex of the albu- 

 men. Herbs or sufFrutescent plants. SAURURACEJE, p. 467. 



Group 5. Flowers perfect or diclinous, frequently destitute of both calyx and 

 corolla. Submersed or floating aquatic herbs. 



Flowers monoecious. Fruit one-celled and one-seeded. 



CERATOPHYLLACE.E, p. 468. 

 Flowers mostly perfect. Fruit four-celled and four-seeded. 



CALLITRICHACE^E, p. 468. 

 Flowers mostly perfect. Capsule several-celled, several-seeded. 



PODOSTEMACE^;, p. 469. 



Group 6. Flowers monoecious or dioecious, not amentaceous. Fruit capsular 

 or drupaceous, with two or more cells, and one (or rarely two) seeds in 

 each. Herbs, shrubs, or trees. 



Fruit mostly dry. Juice milky. Pollen simple. ECPHORBIACEJE, p. 469. 

 Fruit drupaceous. Pollen-grains quaternary. EMPETRACE.S:, p. 470. 



