Volume Ii Part 31 (1/2)

I see that Rhexia grows in Ma.s.sachusetts; and I suppose has two different sets of stamens. Now, if in your power, would you observe the position of the pistil in different plants, in lately opened flowers of the same age? (I specify this because in Monochaetum I find great changes of position in the pistils and stamens, as flower gets old).

Supposing that my prophecy should turn out right, please observe whether in both forms the pa.s.sage into the flower is not [on] the upper side of the pistil, owing to the basal part of the pistil lying close to the ring of filaments on the under side of the flower. Also I should like to know the colour of the two sets of anthers. This would take you only a few minutes, and is the only way I see that I can find out whether these plants are dimorphic in this peculiar way--i.e., only in the position of the pistil (621/1. In Exac.u.m and in Saintpaulia the flowers are dimorphic in this sense: the style projects to either the right or the left side of the corolla, from which it follows that a right-handed flower would fertilise a left-handed one, and vice versa. See Willis, ”Flowering Plants and Ferns,” 1897, Volume I., page 73.) and in its relation to the two kinds of pollen. I am anxious about this, because if it should prove so, it will show that all plants with longer and shorter or otherwise different anthers will have to be examined for dimorphism.

LETTER 622. TO ASA GRAY. March 15th [1862].

...I wrote some little time ago about Rhexia; since then I have been carefully watching and experimenting on another genus, Monochaetum; and I find that the pistil is first bent rectangularly (as in the sketch sent), and then in a few days becomes straight: the stamens also move.

If there be not two forms of Rhexia, will you compare the position of the part in young and old flowers? I have a suspicion (perhaps it will be proved wrong when the seed-capsules are ripe) that one set of anthers are adapted to the pistil in early state, and the other set for it in its later state. If bees visit the Rhexia, for Heaven's sake watch exactly how the anther and stigma strike them, both in old and young flowers, and give me a sketch.

Again I say, do not hate me.

LETTER 623. TO J.D. HOOKER. Leith Hill Place, Dorking, Thursday, 15th [May 1862].

You stated at the Linnean Society that different sets of seedling Cinchona (623/1. Cinchona is apparently heterostyled: see ”Forms of Flowers,” Edition II., page 134.) grew at very different rate, and from my Primula case you attributed it probably to two sorts of pollen. I confess I thought you rash, but I now believe you were quite right.

I find the yellow and crimson anthers of the same flower in the Melastomatous Heterocentron roseum have different powers; the yellow producing on the same plant thrice as many seeds as the crimson anthers.

I got my neighbour's most skilful gardener to sow both kinds of seeds, and yesterday he came to me and said it is a most extraordinary thing that though both lots have been treated exactly alike, one lot all remain dwarfs and the other lot are all rising high up. The dwarfs were produced by the pollen of the crimson anthers. In Monochaetum ensiferum the facts are more complex and still more strange; as the age and position of the pistils comes into play, in relation to the two kinds of pollen. These facts seem to me so curious that I do not scruple to ask you to see whether you can lend me any Melastomad just before flowering, with a not very small flower, and which will endure for a short time a greenhouse or sitting-room; when fertilised and watered I could send it to Mr. Turnbull's to a cool stove to mature seed. I fully believe the case is worth investigation.

P.S.--You will not have time at present to read my orchid book; I never before felt half so doubtful about anything which I published. When you read it, do not fear ”punis.h.i.+ng” me if I deserve it.

Adios. I am come here to rest, which I much want.

Whenever you have occasion to write, pray tell me whether you have Rhododendron Boothii from Bhootan, with a smallish yellow flower, and pistil bent the wrong way; if so, I would ask Oliver to look for nectary, for it is an abominable error of Nature that must be corrected.

I could hardly believe my eyes when I saw the pistil.

LETTER 624. TO ASA GRAY. January 19th [1863].

I have been at those confounded Melastomads again; throwing good money (i.e. time) after bad. Do you remember telling me you could see no nectar in your Rhexia? well, I can find none in Monochaetum, and Bates tells me that the flowers are in the most marked manner neglected by bees and lepidoptera in Amazonia. Now the curious projections or horns to the stamens of Monochaetum are full of fluid, and the suspicion occurs to me that diptera or small hymenoptera may puncture these horns like they puncture (proved since my orchid book was published) the dry nectaries of true Orchis. I forget whether Rhexia is common; but I very much wish you would next summer watch on a warm day a group of flowers, and see whether they are visited by small insects, and what they do.

LETTER 625. TO I.A. HENRY. Down, January 20th [1863].

...You must kindly permit me to mention any point on which I want information. If you are so inclined, I am curious to know from systematic experiments whether Mr. D. Beaton's statement that the pollen of two shortest anthers of scarlet Pelargonium produce dwarf plants (625/1. See ”Animals and Plants,” Edition II., Volume II., page 150, for a brief account of Darwin's experiments on this genus. Also loc. cit., page 338 (note), for a suggested experiment.), in comparison with plants produced from the same mother-plant by the pollen of longer stamens from the same flower. It would aid me much in some laborious experiments on Melastomads. I confess I feel a little doubtful; at least, I feel pretty nearly sure that I know the meaning of short stamens in most plants.

This summer (for another object) I crossed Queen of Scarlet Pelargonium with pollen of long and short stamens of multiflora alba, and it so turns out that plants from short stamens are the tallest; but I believe this to have been mere chance. My few crosses in Pelargonium were made to get seed from the central peloric or regular flower (I have got one from peloric flower by pollen of peloric), and this leads me to suggest that it would be very interesting to test fertility of peloric flowers in three ways,--own peloric pollen on peloric stigma, common pollen on peloric stigma, peloric pollen on common stigma of same species. My object is to discover whether with change of structure of flower there is any change in fertility of pollen or of female organs. This might also be tested by trying peloric and common pollen on stigma of a distinct species, and conversely. I believe there is a peloric and common variety of Tropaeolum, and a peloric or upright and common variation of some species of Gloxinia, and the medial peloric flowers of Pelargonium, and probably others unknown to me.

LETTER 626. TO I.A. HENRY. Hartfield, May 2nd [1863].

In scarlet dwarf Pelargonium, you will find occasionally an additional and abnormal stamen on opposite and lower side of flower. Now the pollen of this one occasional short stamen, I think, very likely would produce dwarf plants. If you experiment on Pelargonium I would suggest your looking out for this single stamen.

I observed fluctuations in length of pistil in Phloxes, but thought it was mere variability.

If you could raise a bed of seedling Phloxes of any species except P. Drummondii, it would be highly desirable to see if two forms are presented, and I should be very grateful for information and flowers for inspection. I cannot remember, but I know that I had some reason to look after Phloxes. (626/1. See ”Forms of Flowers,” Edition II., page 119, where the conjecture is hazarded that Phlox subulata shows traces of a former heterostyled condition.)

I do not know whether you have used microscopes much yet. It adds immensely to interest of all such work as ours, and is indeed indispensable for much work. Experience, however, has fully convinced me that the use of the compound without the simple microscope is absolutely injurious to progress of N[atural] History (excepting, of course, with Infusoria). I have, as yet, found no exception to the rule, that when a man has told me he works with the compound alone his work is valueless.

LETTER 627. TO ASA GRAY. March 20th [1863].