GROUPS AND ORDERS OF APETALOUS EXOGENS. 129 



Gnocp 5. Ovary simple, or of 2 - 4 combincil carpels. Flowers small, bractcate or involucratc, but usually destitute of 

 calyx and corolla. — Submcrgi'd or floatinf; aqviatic herbs. 



93. Ceratoi'Uvllace.e. Flowers mona;cious, axillary. Stamens numerous : anthers sessile. Ovary one-celled, 

 with a sinijle suspended ovule, becoming a beaked achcoium in fruit. — Leaves whorled and dissected, 

 with iililbrm sen;mcnts. 



91. Calhtrichaceje. Flowers poly^^amous, axillary, with a calyx-like 2-leaved involucre. Stamen 1 (rarely 2), 

 with a slender iilamcnt. Ovary 4-lobed, 4-cclled, with a solitary suspended ovule in each cell, in- 

 dehiscent in fruit. — Leaves opposite. 



95. Poeostemacej:. Flowers arising from a spathe. Calyx mostly wanting. Stamens often sohtary, or if more, 

 usually monadclphous. Ovary 2 - 3-ccllcd, with as many distinct styles as cells. Capsule ribbed, 

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



Gboup G. Flowers moncccious or dicecious, 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 cajjsular or drupa- 

 ceous, with two or more cells. 

 9G. Ef PH0RBi.\CE-E. Calyx free from the ovary, sometimes none. Corolla very often wanting the petals j when 

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

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



97. EMPETBACEi:. 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. „ ■ -^ . ■ ■ ^ 



Gaoup 7. Flowers moncccious or dicecious ; 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 LiauiDAMBAR). — Trees or shrubs, except in Ord. 131, many of which are herbs. 



98. JuGLANrACE.s:. Flowers montccious. Sterile flowers in aments. Fertile flowers i'cw, clustered. Calyx 



adherent. Ovary imperfectly 2 - 4-cclIed, 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. CnPULiFERa:. Sterile flowers in aments. Fertile flowers solitary or clustered, furnished with an involucre 



which at length cither includes the fruit, or forms a cup at its base. Fruit a l-cellcd or 1-seeded 

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



100. Mybicace.^. 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. BETDLACEa;. Flowers moncccious, both kinds in aments and commonly achlamydeous. Ovary 2-cclled, with 



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

 or shrubs, with simple leaves. 



102. Salicace^:. Flowers dioscious, both kinds in aments and achlamydeous. Ovary imperfectly 2-ccllcd, with 



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

 — Leaves simple. 



103. BAL3AMiFLn.s:. Flowers monoecious, achlamydeous ; the sterile in conical, the fertile in globose heads or aments. 



Capsules 3-beaked, opening between the beaks, several-seeded, collected with the scales into a hard 

 ball. — Leaves palmately lobed. 



104. PLATANACE.S;. 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. URTicACEa:. Flowers various, often in aments or fleshy heads. Ovary free from the calyx, with a .loUtary 



ovule. Fruit an achenium or utricle. 



[Flora— Vol. 2.] 17 



