Darwin sought to not only produce a new scientific truth, but also to put an end to polygenism, the current scientific discourse on human origins that gave tacit and at times explicit support for slavery: ‘... when the principle of evolution is generally accepted, as it surely will be before long, the dispute between the monogenists and polygenists will die a silent and unobserved death.’ (Charles Darwin, Descent of Man, p. 235)

Saturday, September 1, 2012

Darwin, Gray, and Duppa on the Passion Flower

Repost from RUINS 
Being curious about this neighborhood flower, I looked up some references to it in Duppa, Darwin, and Asa Gray:

 Passiflora incarnata from Fort Tryon Park, New York City

 PASSION-Flower. Of this genus there are no less than thirty-seven different species. This is the common blue Passion- flower, which in a few years may be trained up to more than forty feet high, and the stalks grow to a very considerable size. It grows naturally in Brazil, but is hardy enough to thrive here in the open air, and is now become the most common species in England.
This beautiful tribe of plants was unknown until the discovery of America, and the different species are chiefly found in South America and the islands. It has its name from a fanciful analogy of the different parts of the flower to the Passion of Christ. The Jesuits, who went as missionaries to South America, though they discovered in the three pistilla the representation of the three nails with which our Saviour was nailed to the Cross; the five stamina the five wounds; and the radiant purple Nectary the representation of the rays that might be supposed to have surrounded his head when he expired on the Cross. Duppa, Richard.  1809.  Elements of the Science of Botany, as established by Linnaeus with examples to illustrate the classes and orders of his system, Vol. 1.  London: T. Bensley, Bolt Court for J. Murray, Fleet Street: 27-28.

Order 44. PASSIFLORACEAE . (Passion-Flower Family.)

Herbs or woody plants, climbing by tendrils, with perfect flowers, 5 monadelphous stamens, and a stalked 1-celled ovary free from the calyx, throat 3 or 4 parietal placenta, and as many club-shaped styles; — represented by the typical genus

1. PASSIFLORA, L. Passion-Flower.

Calyx of 5 sepals united at the base into a short cup, imbricated in the bud, usually colored like the petals, at least within; the throat crowned with a double or triple fringe. Petals 5, on the throat of the calyx. Stamens 5: filaments united in a tube which sheathes the long stalk of the ovary, separate above: anthers large, fixed by the middle. Berry (often edible) many-seeded; the anatropous albuminous seeds invested by a pulpy covering. Seed-coat brittle, grooved. — Leaves alternate, generally palmately lobed, with stipules. Peduncles axillary, jointed. Ours are perennial herbs. (Name, from passio, passion, and flos, a flower, given by the early missionaries in South America to these blossoms, in which they fancied a representation of the implements of the crucifixion.)
 1. P. lutea, L. Smooth, slender; leaves obtusely 3-lobed at the summit, the lobes entire; petioles glandless; flowers greenish-yellow (1' broad). — Damp thickets, S. Penn. to Ill. and southward. July -Sept. — Fruit 1/2' in diameter.
 2. P. incarnata, L. Nearly smooth ; leaves 3-cleft ; the lobes serrate ; petiole bearing 2 glands; flower large (2' broad), nearly white, with a tripil purple and flesh-colored crown; involucre 3-leavcd. — Dry soil, Virginia, Kentucky, and southward. May - July. — Fruit of the size of a hen's egg, oval, called Maypops. Asa Gray,  Manual of the botany of the northern United States : including the district east of the Mississippi and north of North Carolina and Tennessee, arranged according to the natural system. New York : Ivison, Phinney, Blakeman, 1867, p. 185-186.    
Passiflora incarnata from Fort Tryon Park, New York City
 (6) Figs, flower. — Passion Flower, (as it is required to impregnate it artificially.) — Asclepias — Flowers not seeding — Put pot of boiled earth on top of House Aristolochia, plant wh require insects to impregnate it
de Beer, Gavin ed. 1960. Darwin's notebooks on transmutation of species. Part III. Third notebook [D] (July 15 to October 2nd 1838). Bulletin of the British Museum (Natural History). Historical Series 2 (4) (July):119-150.
NOTE: See David Kohn in Barrett, Paul H., Gautrey, Peter J., Herbert, Sandra, Kohn, David, Smith, Sydney eds. 1987. Charles Darwin's notebooks, 1836-1844 : Geology, transmutation of species, metaphysical enquiries. British Museum (Natural History); Cambridge: Cambridge University Press.
Darwin also mentions the Passion flower in his discussion on the fertility of hybrids in the Origin of Species:
Now let us turn to the results arrived at by the third most experienced hybridiser, namely, the Hon. and
[page] 250 HYBRIDISM. CHAP. VIII.Rev. W. Herbert. He is as emphatic in his conclusion that some hybrids are perfectly fertile—as fertile as the pure parent-species—as are Kölreuter and Gärtner that some degree of sterility between distinct species is a universal law of nature. He experimentised on some of the very same species as did Gärtner. The difference in their results may, I think, be in part accounted for by Herbert's great horticultural skill, and by his having hothouses at his command. Of his many important statements I will here give only a single one as an example, namely, that "every ovule in a pod of Crinum capense fertilised by C. revolutum produced a plant, which (he says) I never saw to occur in a case of its natural fecundation." So that we here have perfect, or even more than commonly perfect, fertility in a first cross between two distinct
few days perished entirely, whereas the pod impregnated by the pollen of the hybrid made vigorous growth and rapid progress to maturity, and bore good seed, which vegetated freely." In a letter to me, in 1839, Mr. Herbert told me that he had then tried the experiment during five years, and he continued to try it during several subsequent years, and always with the same result. This result has, also, been confirmed by other observers in the case of Hippeastrum with its sub-genera, and in the case of some other genera, as Lobelia, Passiflora and Verbascum. Although the plants in these experiments appeared perfectly healthy, and although both the ovules and pollen of the same flower were perfectly good with respect to other species, yet as they were functionally imperfect in their mutual self-action, we must infer that the plants were in an unnatural state. Nevertheless these facts show on what slight and mysterious causes the lesser or greater fertility of species when crossed, in comparison with the same species when self-fertilised, sometimes depends.
Darwin, C. R. 1859. On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. London: John Murray. 1st edition, 1st issue.
And in his work on the movement of plants: 

By tendrils I mean filamentary organs, sensitive to contact and used exclusively for climbing. By this definition, spines or hooks and rootlets, all of which are used for climbing, are excluded. True tendrils are formed by the modification of leaves with their petioles, of flower-peduncles, perhaps also of branches and stipules. Mohl, who includes with true tendrils various organs having a similar external appearance, classes them according to their homological nature, as being modified leaves, flower-peduncles, &c. This would be an excellent scheme; but I observe that botanists, who are capable of judging, are by no means unanimous on the nature of certain tendrils. Consequently I will describe tendril-bearing plants by natural families, following Lindley, and this will in most, or in all, cases keep those of the same homo-
[page] 49
logical nature together; but I shall treat of each family, one after the other, according to convenience*. The species to be described belong to ten families, and will be given in the following order:—Bignoniaceæ, Polemoniaceæ, Leguminosæ, Compositæ, Smilaceæ, Fumariaceæ, 
Darwin, C. R. 1865. On the movements and habits of climbing plants. London: Longman, Green, Longman, Roberts & Green and Williams & Norgate.  See also Darwin, C. R. 1865. On the movements and habits of climbing plants. [Read 2 February] Journal of the Linnean Society of London (Botany) 9: 1-118, 13 text figures. http://darwin-online.org.uk
Passiflora incarnata from Fort Tryon Park, New York City