ANALYTICAL KEYS TO THE FAMILIES. 



Plants with woody bundles, reproducing by spores. 



Phylum PTERIDOPHYTA, 1. 

 Plants with woody bundles, reproducing by seeds. 



Phylum SPERMATOPHYTA, 8. 



Phylum PTERIDOPHYTA. 



Leaves few, large; stems mostly underground. 



Leaves 4-foliolate, clover-like; spore cases in 



closed pod-like sporocarps. Marsileaceae, 5. 



Leaves not 4-foliolate; spore cases not in sporo- 

 carps. 

 Spore cases in the tissue of a prominent and 



distinct fertile lobe of the leaf. Ophioglossaceae, 4. 



Spore cases formed of outgrowths from the 



surface of the leaf. Polypodiaceae, 1. 



Leaves numerous, small; stems aerial and under- 

 ground. 

 Leaves minute, whorled; stems jointed, hollow. Equisetaceae, 5. 

 Leaves small, not whorled; stems not jointed, 

 solid. 

 Spore cases in the enlarged bases of the leaves; 



stems short, corm-like. Isoetaceae, 7. 



Spore cases in the axils of the leaves; stems 



elongated. Selaginellaceae, 6. 



Phylum SPERMATOPHYTA. 



Ovules and seeds not in a closed cavity, usually on 



the face of an open scale-leaf; stigmas none. Class Gymnospermae, 8. 

 Ovules and seeds contained in a closed cavity sur- 

 rounded by one or more closed and modified 

 leaves forming an ovary; stigmas present. 



Class Angiospermae, 12. 

 Cotyledon one; stem with no distinction into 

 bark, wood and pith (endogenous); leaves 

 usually parallel-veined; parts of the flowers 



nearly always in threes. Sub-class Monocotyledones 3. 



Cotyledons two; stem (with rare exceptions) of 

 bark, wood and pith (exogenous); leaves 

 usually net-veined; parts of the flower in 

 fours, fives or sixes, never in threes. Sub-class Dicotyledones, 72. 



Class GYMNOSPERMAE. 



Fruit a cone. Pinaceae, 9. 



Fruit drupe-like. Taxaceae, 8. 



