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. Suhcass 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
