ILLUSTRATIONS OF INDIAN BOTANY. 183 



of a spurious partition, or membranous extension or band, wliich afterwards thickens, becoming, 

 in the accompanying species, firm, coriaceous and straplike, but in others round, thick and 

 spongy, bearing on its sides the seed. Some however are truly two-celled. 



Character of the Order. Calyx lobed or entire, sometimes spathaceous. Corolla 

 monopetalous, hypogynous, deciduous, irregular, 4-5-lobed or sub-bilabiate, lobes imbricating in 

 aestivation. Stamens usually 4, fertile, didynamous, with a sterile filament, sometimes all fertile ; 

 anthers 2-celled, cells parallel and contiguous or separate and diverging, opening longitudi- 

 nally. Disk glandulose, tumid, embracing the base of the ovary. Ovary 2- rarely 1-celled, 

 ovules several or^ numerous, attached to lateral placentae usually united in the axis by a short 

 process which, with the thickened placentae, afterwards becomes the spongy partition. Style 

 filiform, stigma bilamellate or bifid, lamellae anticous and posticous. Capsule 2-valved, 2-celled, 

 often long, compressed, sometimes spuriously 4-celled, the septum either parallel to the valves, 

 or contrary to them, finally separating and bearing the seeds. Seeds transverse, compressed, 

 winged, exalbuminous ; embryo straight next the hilum, cotyledons flat, follaceous or fleshy. 

 Trees or shurbs, stems erect, scandent, or twining. Leaves opposite, sometimes simple, usually 

 compound, the petiol sometimes produced into a tendril. Stipules none, but sometimes re- 

 placed by accessory leaflets. Inflorescence usually panicled or racemose. 



Affinities. As regards the flowers this order is nearly allied to Pedaliaceoe^ Gesneriacece, 

 AcanthacecE^ and Scrophulariacece^ but is kept distinct from all by its winged seed, provided 

 the section CrescentiecB^ which De Candolle retains, is separated to form a new order, a view 

 m which Botanists now generally coincide, as its retention may be said to break down the 

 essential character of the order. Much stress is laid on the axile position of the placenta?, 

 which Lindley observes "is an indispensable character of this natural order,"' but immediately 

 goes on to observe that "the genus Eccremocarpus, however, appears to be an exception, 

 its placentae being strictly parietal at the time of the expansion of the flower^ and, further, 

 that he long since stated that the placentation of Bignonia radicans is originally of the 

 same nature, the difference between them consisting in the 2 placentse of the latter meeting 

 m the axis and uniting there, while those of Eccremocarpus never touch in the middle. The 

 same seems to be the case in the species here figured (Spathodea adefiophyUaJ, and doubtless 

 will be found in many others, when all have been examined at a sufficiently early stage. 

 I have remarked a similar structure in several species of Acanthacece^ the inflexed valves 

 of which do not quite meet until after the fall of the flower, though they also are said to 

 have axile placentation. But indeed the difference between the fruit of Bignoniacece and 

 Jcanfhacece^ at least as I understand them, is not so great as, at first sight, one might be 

 led to suppose, and neither have, strictly speaking, axile placentae, such as in Scrophulariacecs. 

 The structure of the ovary in both families is nearly the same, and both have bivalved, 2-celled, 

 dehiscent capsules. The essential difference, therefore, exclusive of habit, is found in the 

 spurious partition of Bignoniacece^ and in the mode of dehiscence of the capsule in the two 

 families. In the former (Bignoniaceae) it is either septicidal or locnh'cidal but without elasticity ; 

 in the latter it is always loculicidal. In other words, in the tribe Eiihignoniacece the dehiscence 

 takes place in the line of the placentae, equivalent to septicidal ; the spurious partition, on the 

 sides of which the seeds lie, at the same time separating from the valves, is found loose within 

 the capsule: the septum is then said to be parallel to the valves. In the sub-tribe Catalpe^E 

 }t takes place along the middle or dorsum of the carpels, that is, loculicidally; the partition 

 |s then said to be contrary or with its edges opposite the middle of the valves, which valves, 

 ^ this case, are each made up of two half carpels cohering along their placentary margins. 

 This is precisely what takes place in Acanthacem, with this difference, that in Acanthaceae there 

 IS no free, spurious partition, but the seed are attached to persistent placentary processes, and the 

 calves usually separate with elasticity. The affinity, therefore, between Acanthacew and the 

 sub^ribe CatalpecB is very close. The affinity between Bignoniacece and Scrophulariaceoe, which 

 wndley also places in his Bignonal Alliance, is not so close, for though they associate as well as 

 regards the flower, the placentation differs in being decidedly axile and the seed albuminous, 

 neither of which is trulv the case in Bi^noniaceae or Acanthacew. 



