KEY TO SOME FAMILIES OF SPERMATO- 

 PHYTES. 



CLASS I. 

 GYMNOSPERM^. Ovules not inclosed in an ovary. 



Fruit usually a cone, or berrylike by coherence of scales. Conifers, page 12. 



CLASS IL 



ANGIOSPERM^. Ovules inclosed in an ovary. 



Subclass I. Monocotyledons. Embryo with i cotyledon. .Stem having no 

 distinct zones of bark, wood, and pith. Parts of the flower usually in whorls 

 of 3. Leaves mostly parallel-veined. 



A. Flowers on a spadix or fleshy axis, without calyx or corolla, and without chaffy 

 scales or glumes. 



Marsh herbs with long linear or swordlike leaves, and flowers in cylindrical ter- 

 minal spikes. Typhace^, page 15. 

 Terrestrial plants ; flowers on a spadix surrounded by a spathe. Arace-e, page 18. 



B. Flowers not on a spadix; provided with calyx, or both calyx and corolla. 



Perianth adherent to ovary throughout its length, or apparently so, i.e. ovary inferior. 



Stamens i or 2, gynandrous, flowers very irregular. Orchidace>e, page 26. 



Stamens 3; anthers extrorse, opening lengthwise. Iridace^e, page 25. 



Stamens 6. Flowers borne on a scape from a bulb. AMARYLUDACEiC, page 24. 



Perianth wholly free from the ovary. 



Segments of the perianth all nearly alike in form and color, but in the genus 

 Trillium having 3 green sepals and 3 withering-persistent petals. 



LiLiACE-E, page 19. 

 Perianth of 3 green sepals and 3 deliquescent petals. Commelinace^, page 19. 



C. Flowers with sepals and petals reduced to mere scales and bristles, and inclosed 



in scalelike bracts or glumes. 



Glume, a single scalelike bract; stems solid. Cyperace>e, page 18. 



Glumes of 2 sorts in pairs; stems usually hollow. GraminEvE, page 15. 



Subclass II. Dicotyledons. Embryo with a pair of opposite cotyledons. 

 Stems having distinct zones of bark, wood, and pith. (In herbaceous plants 

 the wood zone is often not hard nor well pronounced.) Parts of the flower 

 mostly in whorls of 4 or 5. 



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