454 



ILLUSTRATIONS OF THE NATURAL ORDERS. 



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

 mas three. Capsule three-valved, loculicidal ; the valves also usu- 

 ally breaking away from a thick central column which bears the 

 seeds. Embryo sti-aight, in fleshy or horny albumen. — Ex. 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, Avith some doubt. They are two 

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

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

 arity is found in the transversely dehiscent anthers. 



881. Ol'll. CtinVOlvulacePB {Convolvulus Famihj). Twining or trail- 

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

 nate, and the flowers regular. Calyx of fi\e imbricated sepals, per- 

 sistent. Corolla supervolute in aestivation ; the limb often entire 

 (Fig. 452). Stamens five, inserted on the tube of the corolla near 

 the base. Ovary 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 



1035 



1041 



1040 



1039 



1036 



1037 



crumpled (Fig. 122, 123). — Ex. Morning-Glory, Bindweed. They 

 contain a peculiar strongly jiurgative resinous matter, Avhich is 



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

 two seeds in each cell 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. 1010. Em- 

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

 separated and laid open. 



