10 ANALYTICAL KEY 



I. Rootstock almost none, the solitary (rarely 2) fronds appear- 

 ing to rise from a cluster of fleshy roots ; lower segment 

 sterile, upper fertile and bearing 2-rowed globular 

 sporangia Botrychium, 47 



I. Rootstock well developed, elongate or stout, the roots 

 fibrous; fronds numerous or the fertile and sterile 

 clearly distinct J. 

 J. Fertile fronds or segments scarcely or not at all leaf-like, 



the sporangia globose or in bead-like rows. 

 Sporangia globose, thin-walled, 2-valved, densely 



crowded, not 2-ranked OSMUNDACEAE, 46 



Sporangia globose and distinct or connected in bead- 

 like chains, firm, 2-ranked Onoclea, 45 

 J. Fertile fronds or segments green and leaf-like, at least 



above ; the sporangia not globose POLYPODIACEAE, 33 



E. Fertile fronds or segments essentially like the sterile. 



Sporangia sessile at the base of a bristle-like receptacle and 

 surrounded by a cup-like involucre ; frond of a single layer 

 of cells HYMENOPHYLLACKAE, 33 



Sporangia stalked, with no bristle-like receptacle; frond of 



more than one layer of cells POLYPODIACEAE, 33 



DIVISION II. SPERMATOPHYTA 



Plants with true flowers containing stamens, pistils, or both. Reproduc- 

 tion normally by seeds containing an embryo. 



SUBDIVISION I. GYMNOSPERMAE 



Ovules not in- a closed ovary. Trees and shrubs with needle-shaped, linear, 

 or scale-like mostly evergreen leaves, and monoecious or dioecious flowers K. 



K. Flowers themselves catkin-like or borne in catkins, which be- 

 come cones or berry-like PINACEAK, ('.'_ 



K. Flowers solitary, axillary ; seed solitary, more or less enveloped 



in a pulpy disk TAXACEAE, 02 



SUBDIVISION II. ANGIOSP^RMAE 



Ovules borne in a closed ovary, which at maturity becomes the fruit. 



CLASS i. MONOCOTYLEDONEM: 



Stems without central pith or annular layers, but having the woody til>rs 

 distributed through them (a transverse slice showing the fibers as dots scat- 

 tered through the cellular tissue). Embryo with a single cotyledon, the 

 early leaves always alternate. Parts of the flower usually in threes or 

 sixes, never iii fives. Leaves mostly parallel-veined. Our species, except 

 in the genus Smilu.r. herbaceous L. 



L. Small lens-shaped, ellipsoidal, or tlask-shape.1 five-swimming 



aquatics without true leaves l.i- MNACKAB, 259 



L. Plants witli stems ami leaves (sometimes scale-like) M. 



