Page:Illustrations of Indian Botany, Vol. 2.djvu/77

Rh 4. A young fruit.

5. The same cut transversely.

6. A seed divided vertically.

7. Cut transversely.

1. Stamens as seen when the corolla is simply removed.

2. The same, the anthers separated to show their lobed form.

3. A detached stamen showing it lobed but not much more so than in Coccinea.

4. Ovary, style and stigmas.

5. The same cut transversely.

1. Male flower, stamens free

2. The same split open, showing the insertions of the stamens and large abortive ovary.

3. (By mistake 8) detached stamens.

4. Female flower and ovary.

5. The same split open to show the styles and stigmas and abortive stamens

OBS. — This figure was prepared from dried specimens, but appears sufficiently perfect to show that § 5 and 6, might without inconvenience, perhaps with advantage be united so far as the stamens are concerned for the anthers of Mukia do not cohere though connivent and less distinctly free than those of Zehneria.

The plate as a whole amply I think establishes the position with which I started, that the sections are too numerous.

 

This, though one of the smallest, is yet, in some respects, a very interesting order. The number of its species seem to amount to only 6 or 7, and form two genera, neither of which are considered of Indian origin. The Papaw tree, the only one met with in India, being introduced from America. This tree is usually supposed to be always diœcious and I have even heard the possibility of the union of the sexes on the same plant questioned. The prevalence of this opinion combined with the general acquaintance, in India, with the usual form of the tree, has induced me, in the accompanying figures, to present unusual forms, partly with the view of removing such erroneous opinions, but principally to illustrate a point in vegetable physiology not generally understood. I allude to power which vegetables possess, in particular circumstances, of developing organs which are usually suppressed. In the first of these plates we have an instance of a ramous specimen of this tree, to show, that though it rarely developes lateral buds, yet, that they exist in the axil of each leaf and are readily developed when the terminal one has been injured. The main trunk of this tree had been injured and many lateral buds are developed and now form vigorous branches. The next presents two panicles of male flowers every branch, of the larger of which, is furnished with one or more fertile flowers : the smaller is the usual form without fertile flowers : the former was taken in June from a tree growing in moist rich soil on the bank of a canal, in the then cool and humid climate of Quilon ; the other grew in Madras. The monoecious plant is also of frequent occurrence in the cool climate of Kandy in Ceylon, but I have never seen a single instance of the kind in the hot dry climate of the Carnatic. This fact affords a strong confirmation of the truth of an observation of Mr. Knight, that he could render melon plants much more prolific of fruit by cultivating them in a very cool atmosphere, almost every flower produced in such circumstances being fertile, while male flowers predominated in opposite circumstances. In the Papaw, this is accounted for by each male flower being furnished with an ovary, usually rudimentary, but which is yet capable of becoming fertile.

The Papaw is, except in the circumstances above mentioned, usually a tree without branches with a cylindrical succulent lactescent stem, of so very rapid growth that it often attains sufficient maturity to bear fruit within 18 months from the time the seed was sown. The leaves which are large digitately palmatifid on long hollow petiols without stipules, form a capacious tuft or crown on the apex : the male flowers form large drooping panicles while the females are nearly sessile.

" Flowers unisexual. Calyx minute, 5-toothed. Corolla monopetalous, inserted into the base of the calyx, in the male tubular and 5-lobed ; in the female divided nearly to the base into five segments. Stamens 10, inserted on the throat of the corolla : anthers introrse, 2-celled, bursting longitudinally ; those alternate with the lobes of the corolla on short filaments, those opposite to the lobes sessile. Ovarium free, 1 -celled : ovules indefinite: stigmas sessile, 5 lobed, lacerated. Placentas 5, parietal. Fruit succulent, indehiscent, 1 -celled. Seeds indefinite, parietal, enveloped in a loose mucous coat : testa brittle, pitted. Embryo in the axis of 