Key to the Families 27 



P. Flowers perfect. 



Plants with flowers in a dense spike (4-7 cm long), borne on the 



margin of a long, 2-edged scape; rhizome aromatic 



694. Acorus, p. 277. 



Plants not as above, the flowers not in spikes; rhizomes not 

 aromatic. 



Carpels 3-6, more or less united, separating at least when 



ripe 14. Juncaginaceae, p. 85. 



Carpels 3, completely united, not separating at maturity. 



36. Juncaceae, p. 290. 



M. Perianth always present, herbaceous or colored, neither scalelike nor 

 bristle-form Q. 



Q. Pistils numerous, in a head or ring 15. Alismaceae, p. 86. 



Q. Pistil one, compound (cells or placentae mostly 3) R. 

 R. Stamens 3. 



Flowers racemose or spicate 14. Juncaginaceae, p. 85. 



Flowers in dense, scaly heads 29. Xyridaceae, p. 282. 



Flowers cymose 36. Juncaceae, p. 290. 



R. Stamens 4 1119. Maianthemum, p. 318. 



R. Stamens 6 S. 



S. Stamens all alike and fertile. 



Ovary of 3-6 carpels, separating at maturity 



14. Juncaginaceae, p. 85. 



Ovary not deeply cleft (often angled or lobed). 

 Divisions of the perianth alike or nearly so. 



Plants rushlike; perianth small, greenish or purplish brown. 



36. Juncaceae, p. 290. 



Plants not rushlike 38. Liliaceae, p. 303. 



Divisions of the pedianth unlike; the 3 sepals green and 2 or 

 more of the petals colored. 

 Stem leaves ovate or oblong, in a whorl of 3; flowers solitary, 



terminal 1138. Trillium, p. 321. 



Stem leave of a linear type, not in whorls; flowers in umbels. . 



33. Commelinaceae, p. 283. 



S. Stamens dissimilar, or only 3 with fertile anthers. 



Perianth of 6 yellow, petaloid segments 



Erythronium americanum, p. 314. 



Perianth of 3 herbaceous sepals and 2 or 3 colored ephemeral petals 



(petals rarely white) 33. Commelinaceae, p. 283. 



Perianth tubular, 6-lobed, mostly colored 



34. PONTEDERIACEAE, p. 287. 



L. Perianth present, adnate to the ovary. 



Stamens 1 or 2; flowers irregular; seeds many.... 50. Orchidaceae, p. 335. 

 Stamens 3 or more; flowers mostly regular or nearly so. 



Plants immersed aquatics 17. Hydrocharitaceae, p. 91. 



Plants terrestrial. 

 Flowers dioecious; jjlants twining; leaves net- veined 



43. DlOSCOREACEAE, p. 330. 



Flowers perfect; leaves parallel-veined. 



Stamens 6 40. Amaryllidaceae, p. 328. 



Stamens 3; leaves 2-ranked 44. Iridaceae, 332. 



Embryo with a pair of opposite cotyledons; leaves net-veined (except in Eryngium) ; 

 parts of the flower mostly in fours and fives; stems formed of bark, wood, and 

 pith, increasing in size by the annual addition of a new layer (rarely two) to 

 the outside, next to the bark (Dicotyledons.) T. 



