BiGNONlALES.] 



BIGNONIACE.E. 



G75 



Order CCLXII. BIGNONIACEiE.— Bignoniads. 



Bignoniae, § 2. Juss. Gen. 137. U789).— IJignoniaceae, R. Brown Prodr. 470. (1810) ; liartl. Or.l. yat. 

 185 ; Endi. Gen. cli. ; Alph. DC. Prodr. y. 1-12. 



Diagnosis. — Bignordal Exogens, with axile placentw, winged sessile seeds icithout albumen, 

 and large leafy cotyledons. 



Trees, shrubs, or occasionally hei'bs, often twining or climbing. Leaves opposite, 

 very rarely alternate, compound or occasionally simple, without stipules. Inflorescence 



tex'minal, somewhat panicled. 

 Calyx divided or entire, some- 

 times spathaceous. Corolla 

 monopetalous, hypogynous, usu- 

 ally ii'regular, 4- o-lobed. Sta- 

 mens 5, unequal : always 1 

 sterile, sometimes 3 ; anthers 

 2-celled, formed noinnally. 

 Ovary seated in a disk, 2-celled, 

 with the carpels anterior and 

 posterior, or spuriously 4-celled, polyspemious ; style 1 ; stigma of 

 2 plates; ovules 00, attached to a solid axile placenta. Capsule 

 2-valved, 2-celled, often long and compressed, sometimes spuriously 

 4.celled, Dissepiment formed from the placenta, which when it is 

 vmdivided cuts the cavity of the ovary into 2 cells, or when it is 

 2-lobed, as is sometimes the case, assumes the appearance of being 

 parietal and forms a 1 -celled ovary, either parallel with the valves, or 

 contrary to them, finally becoming separate, and bearing the seeds. 

 Seeds transverse, compressed, winged ; albumen ; embryo straight, 

 foliaceous ; radicle centrifugal, much smaller than the broad coty- 

 ledons. 



In the mere form of their flower there is nothing to distinguish 

 Bignoniads from the kindi-ed Orders. The distinction lies entirely 

 in the seeds, wliich are winged, sessile, destitute of albumen, and 

 furnished with a large leafy embryo, whose radicle is small and m- 

 conspicuous. They differ from Figworts in their leafy cotyledons 

 and want of albumen ; and from Acanthads, whose embryo is simi- 

 lar, in their winged seeds not attached to hard processes of the pla- 

 centa. Besides which, their calyx is by no means so much imbri- 

 1 cated as in Acanthads. 



The central or axile position 

 of the placenta, is an indispen- 

 sable character of this Natural 

 Order. The genus Eccremo- 

 carpus, however, appears to be 



m 



"'^ 



Fig. CCCCLV. Fi«- CCCCLVI. 



an exception, its placentae being strictl y parietal at the time of the expansion of the 

 Fig. CCCCLV.-Eccremocarpus scaber. 1. cross section of its ovary ; 2. longitudinal section of it ; 



^' Fi|.**CCCCLVI.— Cross section of the same ovary, much more magnified and very young. 



X X 2 



