X KEY TO THE ORDERS AND FAMILIES 



Class 2. ANGIOSPERMAE 79 



Embryo with one cotyledon ; stem endogenous, not differentiated into bark, wood and pith. 



Subclass 1. Monocotylcdoiics. 

 Embryo normally with two cotyledons ; stem exogenous, differentiated into bark, wood and 

 pitli; leaves generally netttd-veincd. Subclass 2. Dicotylcdoncs. 



Suhc\ass I.' MONOCOTVLEDONES 79 



Carpels 1, or when more than one distinct; ovules 1 to each carpel. (Exceptions in Scliciich::cr- 

 iaceac, Vallisncriaccac and Fhocnicaceac ; see also Lcmnaccac.) 

 Flowers not in the axils of chaffy scales (glumes) ; aquatic or marsh plants. 

 Perianth when present never petaloid. 



Perianth of bristles or scales ; monoecious marsh plants. 



Order 1. Pandanales. 

 Flowers in terminal spikes; perianth of bristles. Earn. 1. Typhaccac. 79 



Flowers in terminal heads ; perianth of scales. Earn. 2. Sparganiuccae. 80 

 Perianth fleshy or herbaceous or wanting; aquatic plants with perfect or unisexual 

 flowers. ' Order 2. Naiadales. 



Inflorescence not of two sorts. 



Stigmas 1, disk-like or cup-like. Earn. 3. ZannichelUaccac. 83 



Stigmas 2-4, slender. 



Flowers solitary in the leaf-axils; freshwater plants with spiny-toothed 



leaves. Fam. 4. Naiadaccac. 92 



Flowers on a spadix enclosed by a spathe-like leaf ; dioecious maritime 



plants with ribbon-like leaves. Fam. 5. Zostcraceac. 93 



Inflorescence of two sorts ; spikes bearing perfect, staminate and pistillate flowers ; 



a solitary pistillate flower with elongate filamentous styles in the leaf axils. 



Fam. 6. Lilacaccac. 95 

 Perianth in 2 series, the inner usually petaloid. 



Ovaries superior. . Order 3. Alismales. 



Inner perianth-segments not petaloid ; carpels 3-6, more or less united. 



Fam. 7. Scheuchseriaceae. 96 

 Inner perianth-segments petaloid ; carpels numerous, distinct. 



Fam. 8. Alismaccac. 97 

 Ovary inferior, submerged aquatic plants. Order 4. Hydrocharitales. 



Represented by one family. Earn. 9. Vallisncriaccac 103 



Flowers in the axils of chaffy scales (glumes). Order 5. Poales. 



Glumes 2 to each flower ; stems in our species hollow. Fam. 10. Poaccae. 103 



Glumes 1 to each flower; stems solid. Fam. 11. Cypcraceae. 255 



Carpels united into a compound, 1-3-celled ovary; ovules usually several to each carpel. 

 (Exceptions in Fhocnicaceac and Lcmnaccac.) 

 Inflorescence a spadix with or without a spathe. ( In the Lcmnaccac the spathe is reduced 

 to a small pouch on the back of the minute frond.) 

 Trees or shrubs with compound spadices. Order 6. Phoenicales. 



Represented by one family. Fam. 12. Phocnicaceac. 344 



Herbaceous plants with a simple spadix. Order 7. Arales. 



Large herbs, ours with a stout spadix subtended by a conspicuous spathe. 



Fam. 13. Araccae. 345 

 Minute floating thalloid aquatics. Fam. 14. Lcmnaccac. 346 



Inflorescence various, not a spadix. 



Flowers regular or nearly so ; endosperm present. 



Endosperm mealy; ours a submerged aquatic with a 1-celled ovary. 



Order 8. Xyridales. 

 Represented by one family. Fam. 15. Pontcdcriaccac. 349 



' Endosperm fleshy or horny. Order 9. Liliales. 



Ovary superior or partly inferior in some species of Zyyadcnus. 



Perianth-segments scale-like, not petaloid; herbs with grass-like leaves. 



Fam. 16. Juncaccae. 350 

 Perianth-segments, at least the inner, petaloid. 

 Fruit a capsule (see also Scoliopns) . 



Capsules septicidal ; plants usually from rootstocks (except Zyyadcnus). 



Fam. 17. Melanthaccac. 371 

 Capsule loculicidal (except Calochortus) ; plants from bulbs or corms 

 (except ]'ncca and Nolina). Fam. 18 Liliaccac. 379 



Fruit a berry, except Scoliopns. 



Flowers perfect; erect herbs without tendrils. 



Fam. 19. C oni'allariaccac. 448 

 Flowers dioecious ; vines with tendrils. Fam. 20. Smilacaccac. 458 



Ovary inferior. 



Stamens 6. Fam. 21. Amaryllidaccac. 459 



Stamens 3. Fam. 22. Iridaccae. 461 



