CLASSES, ORDERS, AND GENERA. 
xli 
single, multipartite. Stam. 16 — 20. Germen 1, superior. 
Style filiform and stigma simple. Fruit indehisccnt, 1-seeded. 
p. 388. 
22. Myriophyllum. Flowers axillary or in a lax spike. Cal. of 
4 leaves. Pet. 4, deciduous. Stam. 8. Germen inferior. 
Stigmas 4, sessile. Fruit splitting into 4 achenes. p. 147. 
23. Sagittakia. Flowers solitary, peduncled. Perianth of 6 leaves; 
3 outer herbaceous, 3 inner petaloid. Stam. numerous. Ger- 
mens superior, very numerous, collected into a head, each 
with one style and stigma, p. 471. 
Leaves with stipules adheriny to the petiole. 
24. Poterium. Flowers collected into a head, upper ones fertile. 
Perianth single. Stam. numerous. Filaments very long, 
flaccid. Stigmas penicillate. Achenes 2, invested with the 
hardened perianth, p. 133. 
ff Flowers with a spatha and spadix. 
25. Arum. Spatha of 1 leaf, convolute at the base. Spadix thick, 
naked above, with germens at its base and sessile stamens 
near the middle. Berry 1 -celled, many-seeded, p.475. 
** Barren flowers in catkins or lax spikes. 
26. CUPULIFER/E. Fertile fl. solitary or aggregate or spiked. 
Fruit solitary, or several together within a coriaceous or leafy 
involucre, not winged, p. 415. 
27 Betula. Fertile flowers in cylindrical catkins. Germen and 
fruit compressed, winged, not contained within an involucre, 
p. 395. 
Ord. VII. Monadelpiiia. Stamens united in one set. 
28. Xanthujm. Barren fl. capitate, seated upon a common recep- 
tacle. Perianth single, 5-toothed. — Fert. fl.: Involucre of 1 
piece, prickly, 2-beaked, inclosing 2 1-seeded pistils without 
a perianth. Stigmas protruded. — Leaves netted-veined. 
p. 261. 
29. Pixus. Perianth 0. — Barren fl. in crowded racemose catkins; 
the scales peltate, bearing 2 sessile anthers. — Fertile fl. in an 
ovate catkin ; its scales closely imbricate, 2-flowered, after- 
wards hardened. Style and stigma 0. Pericarp none (except 
the scales of the cone). Leaves parallel-veined, p. 419. 
