EXPLANATION OF PLATE 107.
1. A panicle of flowers of Carica Papaya taken from a male tree, but in this instance having female flowers mixed.
2. A male flower split open, showing the 2 rows of stamens and abortive ovary in the bottom of the tube.
3. One of the female flowers detached and the petals forced open te show the ovary.
4. The same, cut open.
5. A Papaw taken from the same tree smaller than those produced on the female tree, but otherwise perfect.
6. The same cut vertically showing the seed in situ.
7- Portion of a panicle of male flowers the usual form.
8. Male flowers split open.
9 & 10. Back and front views of the stamens.
LXX.—PASSIFLOREÆ.
This like the last can scarcely he viewed as an Indian order, a very few species only, out of nearly 200 described in Botanical works, having yet been met with in Asia. America, especially the warmer provinces is the grand storehouse of these elegant and deservedly much admired flowers.
This family approaches Cucurbitaceae in its tendril hearing stems and diffuse climbing habit, but in scarcely any other well marked particular. Its flowers are very different, its fruit are superior and distinctly parietose, and its, seed are albumenous. Notwithstanding these important differences nearly all Botanists agree in placing these orders next each other, and Jussieu even united them, not however without remarking on the very different position of the ovary in the two tribes. In habit their agreement is so strong that without examination of the flowers or fruit our species of Modecca might readily be referred to Cucurbitaceae, but the slightest examination of either flower or fruit at once shows a wide difference. Lindley however remarks " there can be no doubt that Cucurbitaceae are really little more than Passifloreae with inferior fruit" an opinion we shall consider more at large when we come to consider their affinities. The order is thus characterized.
" Sepals 5 (rarely 4), foliaceous, united below into a short or elongated tube, the sides and throat of which are lined with a eorona composed of filamentous or annular processes. Petals perigynous, inserted between the corona and the calyx-segments, with which last they are as numerous, and alternate, usually almost homogeneous with and shorter than them, very rarely larger than them and with the usual appearance of petals, sometimes wanting. Stamens 5 (very rarely indefinite), monadelphous, usually with processes from the torus between them and the petals: anthers inserted by their base, 2-celled, bursting longitudinally on the inner side (but, from their being often reflexed, apparently opening outwardly.) Ovarium free, I -celled : ovules indefinite, attached to 3 (or very rarely 4), parietal placentae : styles 3 (or very rarely 4), or none. Fruit naked or surrounded by the calyx, 1-celled, usually 3-valved, sometimes dehiscent and loculicide, sometimes fleshy and indehiscent. Seeds indefinite, compressed, with an arillus or strophida: testa brittle sculptured. Embryo straight, in the centre of a thin fleshy albumen : radicle pointing to the hilum."
Affinities. It is an axiom in Botany, in the determination of natural affinities of plants that the nature of every part of the plant must be understood and explained, to enable us to compare one organ with another in different families, and in that way ascertain in what points they associate and in what they differ. This is not always an easy task, and in the present instance, the elucidation of the parts of the flower has given rise to much difference of opinion among the leaders of the science.
Jussieu first described the parts called petals in the above character as an inner division of sepals, and viewed the order as apetalous. DeCandolle so far agrees in this view, as to call the inner row sepals, but nevertheless considers the order polypetalous which, Lindley well remarks, " he is unable to understand on the supposition of the inner series of floral envelopes being calyx," and therefore, with other Botanists considers the outer series as the calyx and the inner as petals, first, because they have the ordinary position and appearance of calyx and corolla, the outer being green the inner coloured, and secondly, because there is no essential difference between the calyx and corolla except the one being the outer and the other the inner of the floral envelopes. Neither Endlicher nor Meisner, both of whom quote his work, seem to coincide in the correctness of this view, since they both describe its floral envelopes as a perigonium corolla like 8-10 cleft, with an outer and inner series, but both arrange the family among orders having
