ILLUSTRATIONS OF INDIAN BOTANY. 189 



cell, attached to cup-shaped, subulate or hooked processes (retinacula) of the placenta ; testa 

 coriaceous, fibrous or loose, often tuberculate, sometimes pilose; albumen none; embryo 

 curved or straight; cotyledons large, roundish; radicle taper, descending and at the same time 

 centripetal, curved or straight. — Herbaceous plants or shrubs; stem and branches nodosely 

 jointed; hairs when present simple, capitate or jointed; leaves often beset with white hair- 

 hke lines (lineoles) under the epidermis which, after breaking the cutula, effurvesce on the appli- 

 cation of an acid. Leaves opposite or, rarely, in fours, exstipulate, entire or serrated, rarely 

 showing a tendency to become lobed, sometimes in unequal pairs. Inflorescence terminal or 

 axillary, in spikes, racemes, fascicles, or panicles. Flowers usually opposite on the spikes, or 

 sometimes alternate, furnished with 3 bracts, of which tbe lateral pair are now and then defi- 

 cient; bracts often large and foliaceous, and then the calyx is usually much diminished in size 

 This large and complex order is essentially distinguished from allothers by its elastic, S-valved 

 capsules and retinacula or placentary processes to which the seeds are so generally attached: 

 for it may truly be said that by these alone it is separated from all others, though it must at 

 the same time be admitted they are not altogether without exceptions; these however are so 

 few as hardly to militate against the general rule. 



Affinities. I Iiave placed this order next Pedaliacece (at tlie end of the Blgnonal group) 

 as forming, through Sesamum, an almost direct transition to that group of orders. AcanihacecR 

 certainly want the spurious partition which divides the 2-celled ovary and capsule of Sesamum 

 into a 4-celled fruit ; and Sesamum is, in like manner, deficient in the retinacula, so remarkable 

 in this family, but otherwise the capsules are very similar ; in both the dehiscence is contrary 

 or through the axis of the septum which remains attached partly to both valves; in both the seed 

 are arranged in two rows in the cells and are exalbuminous ; and, as regards the flowers, it is 

 almost impossible to draw distinctions in a family where almost every form and variation are 

 to be met with, but in both they are irregular. Pedaliacf-ce and Jcanthacece being thus closely 

 allied, it follows that the nearest affinities of AcanthacecB are Bignoniaceoe^ on the one side, and 

 Pedaliacece on the other, to which 1 would add Schrehereoe, which I now view as the type of 

 an order, but for the present reduce to a sub-order appertaining to this group. Formerly 

 Acanthacece were considered rather nearly allied to ScrophulariacecB, but from which they are 

 removed by their parietal, not axile, placentation and exalbuminous seed. But though these 

 two great orders of irregular flowered plants are thus kept distinct by characters, they occa- 

 ..sionally so far interblend in habit that they might, %ut for the fructification, be mistaken for each 

 other. Hence, having the characters of the Bignonal set of orders strongly marked, and to 

 some extent the habit of ScrophulariacecSy they seem to occupy a suitable station here, as form- 

 ing the connecting link between them. 



Geographical Distribution. This is a, peculiarly, tropical order, for, though not con- 

 fined to the tropics, they rarely extend beyond the warm regions bordering them. Two or three 

 are found in Southern Europe and North America, and some in Australia. In India, tropical 

 America, and Africa, they abound. In the Indian peninsula the proportion of Acanthacea 

 equals or perhaps exceeds, in the number of its species, most other dicotyledonous orders ; 

 Legumenosce, and perhaps Composlta;, being, I fancy, almost the only ones by which it is, to any 

 considerable extent, exceeded. As regards Southern India, I suspect species of iU Acnnthaceoe 



as numerous as those of Composite. They are found in all soils and situations, 

 .„ :„ .1 .. J 3 r.^A t^ ih^ ..f-^T^rrocf V^crh*. find eouallv on the sea shore and tons 



are about 



of our highest mountains : they are numerous on the highest ranges ot tne A eiiguerries. i ueir 

 forms are equally variable, ranging from very minute herbs up to moderate sized 8brut)8. 



^, PKOPEKTI.S AKD Uses. These are not important. Some, such as ^n£^^^^^^^ 



being intensely bitter and as such used, either singly or in combina ion as a tome. Some ^ e 

 used in the arts as dyes, and several are most deservedly admitted into the parterre, as affordiiig 

 inost ornamental subjects for the garden and flower border. But niore generally they can at 

 best be designated as weeds, harlng neither use nor beauty to recommend them to our attention. 



