Page:Illustrations of Indian Botany, Vol. 2.djvu/216

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112

ILLUSTRATIONS OF INDIAN BOTANY-


Affinities. Passing over the relationship of this family with the others referred to the class Campanulinece, which scarcely require to he further insisted on, as they have heen adverted to in the remarks on hoth the class and preceding order, I proceed to offer a few observations on more distant affinities. Assuming that the class forms a circle (but which requires to be verified), or group of orders which are really more nearly related to each other than to any others in the system, we may look round to see what others are most nearly related to it. Among these, the Bicornes (Ericales Lind.), through Vucciniacece, occupy a prominent place. It is true the bulk of that group have inferior flowers, but a similar structure is also occasion- ally found in true Campanulinece, while the alternate leaves, plurilocular ovary, indefinite ovules, and albuminous seed, are common to both, as is, in many instances, the loculicidal dehiscence, to which Vacciniacece add epigynous insertion of the flowers. The Caprifoliaceous group, in- cluding Rubiacece, on the other side, presents many points of affinity in some of their genera, especially Hedyotidece, which have valvate aestivation, and considerable similarity of habit, while others are widely distinct. Composite form a third allied group, but the almost uniform monos- permous fruit, exalbuminous seed, and remarkable venation of the corolla, easily keep them distinct, equally from this as from all other families. Indeed, duly considering the importance of the differences in comparison with the points of affinity, the relationship of the Aggregata? and Campanulinae does not appear to me so near as most Botanists seem to view it. Some of the points on which considerable stress is laid, partaking probably more of the nature of analogies than affinities. These are all Epigynous groups, except Bicornes which forms the transition to the Hypogynous ones.

Geographical Distribution. This is a pre-eminently extra-tropical family, only about SO out of 500 species being found within the tropics. They also prefer alpine regions, the greatest number of species being found in alpine countries: the Alps of Europe: the Caucassian, Altai, and Himalayan ranges, being all centres of habitation in the Northern hemisphere, while the Cape of Good Hope forms the principal one in the Southern. According to Alph. D. C., it is between the 36th and 47th degrees of Northern latitude the greatest number of species is found, and he considers the mountains just named as their true native country.

Properties and Uses. Under this head little can be said. The milky juice of some is acrid, but the opposite property is their predominating characteristic, and some few are used as food; none, I believe, are held in esteem in medicine. As ornamental plants many are in great request.

Remarks on Genera and Species. The flora of the Indian Peninsula affords but small scope for observations on this head, as about 7 or 8 species comprise the whole list. Of these, I have three referable to the genus Wahlenbergia, one of which was long referred to the order Rubiaceae, under the name of Dentilla erecta, the other two are alpine plants, very nearly related, and both found on the Neilgherries.

Of Campanula, certainly three species are found on the Neilgherries, all of which are figured in the Icones. The one given here, seems to me a capitate variety of C. fulgens, rather than a distinct species, but being so different in appearance, I have thought it deserving of re- presentation as well as the others. The accompanying analysis I have partly taken from other species. These two genera, Campanula and Wahlenbergia, are not easily distinguished, except when in fruit, the mature capsule supplying the essential distinguishing marks. In Campanula, the capsule opens by lateral pores or valves (see Figs. 10, 11, Plate 136), in Wahlenbergia, the dehiscence takes place on the apex (see Fig. 12, Plate 136), in other respects the structure of the two genera is very much alike. The position of the pores in the capsule of Campanula varies, and afford valuable sectional marks by which to group the numerous species of that genus. In some they are seated near the base, and in others near the apex (see Figs. 10, 11). In the former case the capsule is usually drooping, in the latter erect. The genus is further divided into sections and groups by certain appendages of the calyx, being present in one series and absent in another, by some having the capsule 5-celled, others 3-celled. With the aid of