454 



ILLDSTEATIONS OF THE NATURAI- ORDERS. 



axis, bearing few or numerous ovules : styles united into one : stig- 

 mas thi'ee. Capsule tliree-valved, loculicidal ; the valves also usu- 

 ally breaking away from a thick central column which bears the 

 seeds. Embryo straight, in fleshy or homy albumen. — IHx. Pole- 

 monium (Greek Valerian), Phlox, Gilia. Chiefly North Amer- 

 ican ; many are very common ornamental plants in cultivation. To 

 this order Diapensia and Pyxidanthera (formerly the order Dia- 

 pensiacece) are now appended, with some doubt. They are two 

 low, tufted or prostrate, suifruticose plants, with crowded and ever- 

 green, heath-like leaves, and solitary flowers : their principal peculi- 

 arity is found in the transversely dehiscent anthers. 



881. Ol'll. ClinVolVUlaCCEe {Convolvulus Family). Twining or trail- 

 ing herbs or shrubs, with more or less milky juice ; the leaves alter- 

 nate, and the flowers regular. Calj'x of five imbricated sepals, per- 

 sistent. Corolla supervolute in asstivation ; the limb often entire 

 (B^ig. 452). Stamens five, inserted on the tube of the corolla near 

 the base. Ovai-y free, two- to four-celled, with one or two erect 

 ovules in each cell. Capsule two- to four- (or by obliteration one-) 

 celled ;. the valves often falling away from the persistent dissepi- 

 ments (septifragal, Fig. 587). Seeds large, with a little mucilagi- 

 nous albumen : embryo curved, and the foliaceous cotyledons usually 



crumpled (Fig. 122, 123).— ^a;. Morning-Glory, Bindweed. They 

 contain a peculiar strongly purgati\e resinous matter, which is 



riG. 1035. Ipomoea purpurea, 1036. The pistil, 1037. Section of the capsule, and of the 

 two seeds in each ceil. 1038. Capsule (reduced in size), when the valves have fallen away from 

 the dissepiments ; and one of the seeds. 1039. Magnified cross-section of a seed. 1040. Em- 

 bryo, with the leaf like two-lobed- cotyle'dons spread out. 1041. Same, with the two cotyledons 

 separated and laid open. 



