GROUPS AND ORDERS OF APETALOUS EXOUEJNS. 



129 



Group 5. Ovary simple, or of 2 - 4 combined carpels. Flowers small, bracteate or involucrate, but usually destitute of 

 calyx and corolla. — Submerged or floating aquatic herbs. 



93. Ceratophyli.ace.e. Flowers monoecious, axillary. Stamens numerous : anthers sessile. Ovary one-celled, 



with a single suspended ovule, becoming a beaked achenium in fruit. — Leaves whorled and dissected, 

 with filiform segments. 



94. CallitrichacejE. Flowers polygamous, axillary, with a calyx-like 2-leaved involucre. Stamen 1 (rarely 2), 



with a slender filament. Ovary 4-lobed, 4-celled, with a solitary suspended ovule in each cell, in- 

 dehiscent in fruit. — Leaves opposite. 



95. PoDosTEMACEiE. Flowers arising from a spathe. Calyx mostly wanting. Stamens often solitary, or if more, 



usually monadelphous. Ovary 2 - 3-celied, with as many distinct styles as cells. Capsule ribbed, 

 with numerous seeds. — Leaves mostly cut into capillary segments. 



Group G. Flowers monoecious or dioecious, sometimes furnished with both petals and calyx, but often destitute of both, 

 not amentaceous. Ovary 2 - several-celled, with one or two ovules in each cell. Fruit capsular or drupa- 

 ceous, with two or more cells. 

 9G. EuphorbiacejE. Calyx free from the ovary, sometimes none. Corolla very often wanting the petals; when 

 present, distinct. Styles distinct. Fruit capsular, separating into several (often three) carpels or 

 cocci, which open elaslically by one or both sutures. — Juice often milky. 



97. Empetrace.33. Calyx consisting of imbricated sepals. Stamens few, as many as the inner sepals. Ovary 



free, 2 - 9-celled, with a single erect ovule in each cell. Fruit drupaceous (sometimes dry), with 

 2-10 bony nucules. 



Group 7. Flowers monoecious or dioecious ; the sterile and often the fertile also in aments, or in heads or spikes, either 

 furnished with a calyx or achlamydeous. Ovary one - several-celled, but the fruit always one-celled (except 

 in Liquidamear). — Trees or shrubs, except in Ord. 131, many of which are herbs. 



98. JuGLANrACE.^3. Flowers monoecious. Sterile flowers in aments. Fertile flowers few, clustered. Calyx 



adherent. Ovary imperfectly 2 - 4-celled, but with a single ovule. Fruit drupaceous; the epicarp 

 somewhat fleshy and coherent, or coriaceous and dehiscent. Endocarp bony. Seed oily, without 

 albumen. — Leaves pinnated. 



99. Cupuliferje. Sterile flowers in aments. Fertile flowers solitary or clustered, furnished with an involucre 



which at length either includes the fruit, or forms a cup at its base. Fruit a 1-celled or 1-seeded 

 nut. Seed without albumen. Cotyledons thick and fleshy. — Leaves simple. 



100. Myricace.33. Flowers monoecious, both kinds in aments and achlamydeous. Ovary one-celled, with a single 



ovule. Fruit dry or drupaceous. — Shrubs, with simple leaves, dotted with resinous glands. 



101. BETULACEiE. Flowers monoecious, both kinds in aments and commonly achlamydeous. Ovary 2-celled, with 



a single ovule in each cell. Fruit membranaceous or samara-like, one-celled, one-seeded. — Trees 

 or shrubs, with simple leaves. 



102. SALiCACEiE. Flowers dioecious, both kinds in aments and achlamydeous. Ovary imperfectly 2-celled, with 



many ovules : styles or stigmas 2. Fruit follicular, 2-valved. Seeds numerous, with a silky coma. 

 — Leaves simple. 



103. Balsamifluje. Flowers monoecious, achlamydeous ; the sterile in conical, the fertile in globose heads or aments. 



Capsules 2-beaked, opening between the beaks, several-seeded, collected with the scales into a hard 

 ball. — Leaves palmately lobed. 



104. Platanacej;. Flowers monoecious, in globose heads, achlamydeous. Fruit a one-seeded nut, with bristly 



hairs at the base, collected into a compact ball. — Leaves palmately lobed. 



105. Urticace-ZE. Flowers various, often in aments or fleshy heads. Ovary free from the calyx, with a solitary 



ovule. Fruit an achenium or utricle. 



[Flora — Vol. 2.] 



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