KEY TO THE FAMILIES/ 



Plants with woody and vascular tissues, producing spores — 



Subkingdom of Pteridophyta 

 Plants producing seeds. Subkingdom of Spermatophyta 



Pteridophyta. 



1. Leaves broad, entire or dissected. -------2 



1. Leaves scale-like or awl-like. --------4 



2. Vernation straight or inclined. ----- l Ophioglossaceae 



2. Vernation coiled, -----------3 



3. Sporanges round or nearly so, in panicles or spikes, - - 2 Osmundaceae 

 3. Sporanges on the back or margin of the leaf-blades, terrestrial or 



epiphytic plants, --------3 Polypodiaceae 



4. Leaves scale-like, plants terrestrial. --------5 



4. Leaves awl-like, plants aquatic, ----- 7 Isoetaceae 



5. Spores all alike, ----------6 



5. Spores of two sizes, ------ 6 Selaginellaceae 



6. Stems leafy. ----------4 Lycopodiaceae 



6. Stems and branches almost naked, ----- 5 Psilotacae 



Spermatophyta. 



Ovules not contained in an ovary. ----- Class of Gymnospermae 

 Ovules contained in an ovary ------ Class of Angiospermae 



GYMNOSPERMAE. 



1. Plants growing by a single terminal bud; low, palm-like. - 8 Cycadaceae 

 1. Plants growing by terminal and lateral buds; shrubs or trees with 



scale-like or needle-like leaves, -------2 



2. Carpellary scales with bracts, not peltate. - - - - 9 Pinaceae 



2. Carpellary scales without bracts, peltate or fleshy, - - 10 Juniperaceae 



ANGIOSPERMAE. 



Leaves generally parallel- veined, flowers usually 3 or 6 parted — 



Subclass of Monocotyledones, page 10 

 Leaves generally pinnately or palmately veined, flowers rarely 3 or 6 parted — 



Subclass of Dicotyledones, page 1 1 



• The numbers before the names of the Families indicate the order in which they 

 are described and analyzed in the Key to the Genera and Species, page 19. 



