XLII.-GERANIACEAE.
This order maybe viewed as almost entirely of extra- tropical origin, for though a few species are indigenous within the tropics, these are almost invariably found on the higher hills where temperature is reduced by elevation. The Indian Peninsula seems generally unfavourable to the production of plants of this order, since, so far as yet known only one species has been found native even on the highest hills, and in Ceylon the same species only occurs. It consists of herbaceous or suffruticose plants, with the stems usually jointed, the leaves opposite below, and frequently alternate above, palmately nerved and cleft, or pinnatifid, and furnished with two foliaceous stipules. The flowers are more or less irregular, bisexual, paired, or umbelled, seldom solitary, on axillary, or occasionally, leaf opposed peduncles.
Sepals 5, persistent, imbricated in aestivation, sometimes produced at the base into a spur, connate with the pedicel. Petals 5, sometimes 4, or wanting, by abortion, unguiculate, equal and hypogynous, or unequal, and either connected at the base or inserted on the calyx ; aestiva- tion twisted. Stamens usually monadelphous at the base, hypogynous, or pcrigynous, rarely free, twice or thrice as many as the petals. Ovarium 5-celled, with two ovules in each, styles 5, cohering round a central elongated axis or torus (gynobase). Fruit, of 5 membranous 1 -celled, indehiscent carpels, which are at first close pressed to the gynobase, each ending in its style, which is closely adnate to the angles of the axis, but afterwards twists variously from the base to the apex, and carries the pericarp with its enclosed solitary seed along with it. Seed peritropal, albumen none. Embryo curved, radicle superior, but with its point bent down towards the hilum. Cotyledons foliaceous.
Affinities. Nearly all Botanists agree in associating this order with the three following ones, and some, among whom is Mr. Arnott, consider them as either so many sub-orders or at all events members of a class. Meisher adopts this last suggestion and combines them under his class Geranioidece. DeCandolle and Lindley, however remove Linece, the latter Botanist, on account of its wanting the gynobasic structure, and place them near Car yophyllacene, while Bartling retains Lineae here, but separates Balsamineae and places them among his " Or dines insertee sedis." Amidst such conflicting opinions none but the highest authority can deter- mine the place these orders ought to occupy, and as I am far indeed from thinking myself quali- fied to solve the difficulty I leave the matter as I find it: but, were it part of my plan to re- arrange in place of merely to illustrate the orders as they stand in our Prodromus, I think I should revert to DeCandolle's arrangement from thinking Lineae more nearly allied to Caryophyllaceae and Malvaceae, than to Geraniaceae and Balsamineae, nor can I feel surprised that Bartling ex- presses himself doubtful of the place which Balsamineae ought to occupy, for, the order, though itself well defined, is certainly a very curious one in some points, especially in its very irregular flowers and peculiar character and dehiscence of its fruit, the normal structure of which, until elucidated by Hydrocera could not be so satisfactorily explained. Lindley in his 4th group of Polypetalous plants, Gynoba'siosae, associates a series of 10 orders all participating in this (gynobasic) structure, arranged under four sub-groups or Alliances, and thus, excludin g Lineae, brings together a very extensive and natural assemblage of plants, agreeing in more or less distinctly, possessing a gynobase, some it is true Jess evidently so than other.?, but in all distinguishable. In addition to its affinities with the Gynobasic group Geraniaceae ap- proaches Malvaceae in its lobed stipulate leaves, monadelphous stamens, and convolute embryo : from Oxalideae it is separated by its beaked fruit, stipulate leaves, and absence of albumen which is present in Oxalideae, in habit, and some other points, it approaches Ampelideae.
Geographical Distribution. A very extensively but unequally distributed order. In Europe several are found as well as in North America, but most abundant at the Cape of Good Hope. In Asia a few are found, Mr. Koyle states that about 15 are natives of the Himalayas, one only has yet been found in the Indian Peninsula and Ceylon, and that confined to the ele- vated regions of the Neilgherries and Pulney mountains in the former; and in the latter to the most elevated portions of the Island. The Cape is remarkable for the number of its Gera- niums, or rather Pelargoniums, now so generally cultivated all over the world, and esteemed, not less, on account the richness of the colours of their flowers, than on account of the strong and peculiar fragrance of their leaves.
Properties and Uses. Under this head I have nothing to offer, some of the species are astringent, and the root of one North American species has received, in allusion to this pro- perty, the name of Alum root. They have generally an aromatic or resinous flavour.
EXPLANATION OF PLATE 59.
1. Flowering branch of Geranium affine, natural size.
2. A flower.
3. The same, the petals removed to show the stamens and ovary.
4. Back and front view of the stamens.
5. Ovary detached.
6. The same cut vertically, showing the two super- posed ovules, but incorrectly represented ascending.
6. The same cut, vertically.
7. A fruit near maturity.
8. The same, after the carpels have become detached from the Gynobase.
9. A carpel opened, showing the position of the seed.
10. A seed.
I L. The same dissected, showing the embryo in situ. 12. Embryo removed — all more or less magnified.
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GERANIUM AFFINE. (W. & A.)