From W. E. Darwin 22 March [1864]
Summary
Sends drawings of the pollen from Chinese Primula plants with styles and pistils of different lengths; observations on sizes and condition of their pollen.
| Author: | William Erasmus Darwin |
| Addressee: | Charles Robert Darwin |
| Date: | 22 Mar [1864] |
| Classmark: | DAR 108: 86–7, 175–7 |
| Letter no: | DCP-LETT-4434 |
Matches: 15 hits
- … Sends drawings of the pollen from Chinese Primula plants with styles and pistils of …
- … different lengths; observations on sizes and condition of their pollen. …
- … quite perfect with very little imperfect pollen. No 3 had tolerably short pistil (tho’ I …
- … 3 had to open the stamens under 1 inch & get the pollen out. The …
- … seem generally to have more imperfect pollen & to vary in size very much. I can easily get …
- … column : ‘Short-styled | Long-stamen & bigger pollen’ pencil Top of 2d column : ‘Equal to …
- … also sent sketches of Primula sinensis pollen on 12 March 1864 and with his letter of [15 …
- … that I had to dissect the stamens of 8 or 10 flowers to get the pollen I have drawn, there …
- … was a great deal imperfect pollen, but the large ones drawn seemed perfect grains. No (4) …
- … I was so surprised at the various sizes in pollen of No 2. that I got another M. styled …
- … as no (3). I am sure I did not mix the pollens as I did them on separate glasses, & in No …
- … CD discussed William’s examination of the pollen of the plants here numbered 3 and 5 in ‘ …
- … pp. 220 and 222, noting that the large pollen sizes were probably due ‘not to their …
- … the high number of small and shrivelled pollen grains explained the fact that although the …
- … probably means that he was surprised by the pollen of the plant in the sketch numbered 3, …
From W. E. Darwin 18 May [1864]
Summary
Sends Pulmonaria anthers, with measurements of styles and pollen counts.
| Author: | William Erasmus Darwin |
| Addressee: | Charles Robert Darwin |
| Date: | 18 May [1864] |
| Classmark: | DAR 110: A83–6, A94 |
| Letter no: | DCP-LETT-4500 |
Matches: 12 hits
- … Sends Pulmonaria anthers, with measurements of styles and pollen counts. …
- … bad Long styled out of 193 pollen grains 140 were good 53 — bad. if you like, I will …
- … tell me. I cannot judge wh. has most pollen. I got Mamma’s letter about Menyanthes. I …
- … 3 of the others. So I took it off the glass after drawing and compared its pollen with …
- … long styled pollen, and there is no doubt that it is long styled. x I know also to be long …
- … concluding that from the condition of the pollen in the long-styled form, and from the …
- … calculation of the comparative bad & good pollen in the long & short. of course it cannot …
- … to guess, also I dare say in some cases pollen tipped up on end or squashed may have …
- … more imperfect in the long than in the short. I took pollen from 2 plants of each kind. …
- … I found as follows in Short styled out of 265 pollen grains 247 were good 18 — …
- … William had already observed smaller pollen grains from long-styled forms of Pulmonaria …
- … asked for this comparison of good and bad pollen grains from the short-styled and long- …
From W. E. Darwin 5 August 1862
Summary
Has read CD’s long letter on Lythrum and agrees with it. Is examining the pollen of the different types.
| Author: | William Erasmus Darwin |
| Addressee: | Charles Robert Darwin |
| Date: | 5 Aug 1862 |
| Classmark: | DAR 27.2 (ser. 2): 32 bis, DAR 162: 92 |
| Letter no: | DCP-LETT-3683 |
Matches: 11 hits
- … long letter on Lythrum and agrees with it. Is examining the pollen of the different types. …
- … make it more difficult to judge of the sizes Short stamen’s pollen from same flower under …
- … same power — Long stamens pollen from long styled Lythrum. — open flower— anther valves …
- … of the same height as the stamens from which they got the pollen; I mean to look if the …
- … shorter stamens on all have yellow pollen, because then you see each pistil …
- … will be impregnated by one sort of pollen either green or yellow, and it …
- … will be so odd that the pollen of long stamens of the long styled plants should be yellow …
- … think it is quite certain that the yellow pollen deceived me; but I remember thinking that …
- … the anthers seemed less open, and the pollen softer; but when I class the plants I will …
- … Lucida and measured by micrometer of the pollen of L. styled you will see there is a …
- … I think I found a Long styled with green pollen this morning—but will look at it again, …
From W. E. Darwin [after 19 May 1864]
Summary
[Outline sketches of pollen from long- and short-styled yellow cowslips and from a red cowslip.]
| Author: | William Erasmus Darwin |
| Addressee: | Charles Robert Darwin |
| Date: | [after 19 May 1864] |
| Classmark: | DAR 108: 83 |
| Letter no: | DCP-LETT-4369 |
Matches: 7 hits
- … Outline sketches of pollen from long- and short-styled yellow cowslips and from a red …
- … have not been found. It is not known who struck through the sketch of red cowslip pollen. …
- … E. Darwin to W. E. Darwin, [18 May 1864] , CD had asked that the cowslip pollen also be …
- … sketched dry; the pollen in this memorandum appears to …
- … be dry compared with the pollen in the memorandum from W. E. Darwin of [30 …
- … filed by CD with the sketch of wet cowslip pollen on which he recorded measurements by …
- … William of both dry and wet cowslip pollen, ‘1864–1865’ (see memorandum from W. E. …
From William Erasmus Darwin [late February–May 1865]
Summary
[Outline sketches of pollen from short-styled yellow primrose and from long-styled yellow and red primroses.]
| Author: | William Erasmus Darwin |
| Addressee: | Charles Robert Darwin |
| Date: | [late Feb–May 1865] |
| Classmark: | DAR 108: 89a |
| Letter no: | DCP-LETT-4729 |
Matches: 8 hits
- … Outline sketches of pollen from short-styled yellow primrose and from long-styled yellow …
- … Oxlips’ added red crayon Verso : ‘Size of Pollen in long-styled Red Primrose’ pencil ; ‘ …
- … 3 and 5, below. This sketch of the pollen-grains of Primula vulgaris under magnification …
- … forms part of a series of diagrams of the pollen of Primulaceae made by William in the …
- … plants’ , p. 421, CD described the pollen of the red (purple) long-styled primrose as ‘of …
- … William made this observation after the pollen from the red long-styled primrose was sent …
- … 19 May 1864]). CD believed that differences in pollen size and in the size of some flower …
- … may have intended to use the data on primrose pollen in his ongoing investigation into the …
From W. E. Darwin 8 May [1863]
Summary
Describes the structure of Corydalis and its arrangement for making pollen accessible to bees.
| Author: | William Erasmus Darwin |
| Addressee: | Charles Robert Darwin |
| Date: | 8 May [1863] |
| Classmark: | DAR 76: B188–90 |
| Letter no: | DCP-LETT-4147 |
Matches: 9 hits
- … the structure of Corydalis and its arrangement for making pollen accessible to bees. …
- … arrangement making the pistil carrying the pollen in position for another flower. I am …
- … containing two heads of Anchusa. The pollen of short pistilled is decidedly the largest …
- … enclosing it entirely, as soon as the pollen is mature it all falls into the cuplike- …
- … fall back till the stigma cup is full of pollen. As soon as the back petal falls back, the …
- … out the pistil with a bound. Carrying the pollen with it the stigma and style on bounding …
- … itself at base of groove nearly all the pollen is pulled out by the friction and is left …
- … stigma almost bare to receive other pollen. So as to prevent the proboscis penetrating …
- … William’s observations on the sizes of pollen-grains in the different forms of flower in …
From W. E. Darwin 8 May [1866]
Summary
Describes the floral structure of broom, particularly the form of the varying anthers. Encloses drawings of anthers and pollen.
| Author: | William Erasmus Darwin |
| Addressee: | Charles Robert Darwin |
| Date: | 8 May [1866] |
| Classmark: | DAR 76: B52, 66–72 |
| Letter no: | DCP-LETT-3144 |
Matches: 9 hits
- … particularly the form of the varying anthers. Encloses drawings of anthers and pollen. …
- … and examined it: I enclose outlines of pollen grains, also sketches of anthers, though you …
- … is not much difference in the two sets of pollen, which is odd as the the arrangements are …
- … that is, their stamens shed half their pollen before the stigma of the same flower became …
- … 2. CD was interested in the sizes of pollen-grains from stamens of different lengths in …
- … William had previously sketched and measured pollen-grains from several of those species ( …
- … 248–52). CD did not mention the size of pollen-grains in his discussion of Sarothamnus …
- … with adnate anthers always shed their pollen before the others; as the flower gets old the …
- … are certainly larger & I think have more pollen than the short ones. I have just taken up …
From W. E. Darwin [30 April 1864]
Summary
[Outline sketches of pollen from long- and short-styled yellow cowslips and from red cowslip, magnified 350x.]
| Author: | William Erasmus Darwin |
| Addressee: | Charles Robert Darwin |
| Date: | [30 Apr 1864] |
| Classmark: | DAR 108: 84 |
| Letter no: | DCP-LETT-4478 |
Matches: 5 hits
- … Outline sketches of pollen from long- and short-styled yellow cowslips and from red …
- … 30 th 1864’ ink Below sketch of red cowslip pollen : ‘Mid-styled i.e. style just below & …
- … of their original size. William sketched pollen of the long-styled and short-styled forms …
- … of flowers , pp. 234–8. In another sketch of pollen from the same three forms of cowslip, …
- … two of William’s sketches of dry and wet pollen. For CD’s ongoing work on the relationship …
From W. E. Darwin 14 April [1864]
Summary
Observations on [length of style and length of filament and stigmas of] Pulmonaria.
| Author: | William Erasmus Darwin |
| Addressee: | Charles Robert Darwin |
| Date: | 14 Apr [1864] |
| Classmark: | DAR 110: A68–74 |
| Letter no: | DCP-LETT-4462 |
Matches: 9 hits
- … affect son | W. E D. I can do as much pollen work as ever you like 2.1 but … plant 2.2] …
- … circled red crayon Verso of enclosure 1 : ‘Pollen-grains’ pencil Enclosure 2 : ‘2’ red …
- … 13 th ’ pencil Verso of enclosure 2 : ‘Shape of stigma and size of pollen-grains’ pencil …
- … this seems the same as in long styled) The pollen in the 2 short styled kinds is exactly …
- … 2 Longstyled, & you see the short styled pollen is decidedly the largest I have made …
- … size. CD believed that differences in pollen sizes and in the relative sizes of some other …
- … styled anthers have much [ inter ]larger pollen grains according to William than long- …
- … this plainly’. CD discussed comparative pollen sizes of Pulmonaria angustifolia in Forms …
- … flowers , p. 106. He also concluded that the pollen of the shorter-styled form was larger …
From William Erasmus Darwin [15 March 1864]
Summary
Has drawn all three forms of primroses CD sent "with same result". Has found no pink variety with middle style.
| Author: | William Erasmus Darwin |
| Addressee: | Charles Robert Darwin |
| Date: | [15 Mar 1864] |
| Classmark: | DAR 108: 85, 173–4 |
| Letter no: | DCP-LETT-4416 |
Matches: 8 hits
- … middle-styled seems very imperfect in its pollen, but if any thing is the least bit bigger …
- … one flower of the middle seemed to have pollen not unlike Short styled but it was so very …
- … reference to earlier sketches of Primula pollen (see n. 3, below). The Tuesday between …
- … their original size, are apparently of pollen from the Chinese primrose ( P. sinensis ) ( …
- … 108: 88, dated 12 March 1864. These are of pollen from short-styled and long-styled forms …
- … flowers , p. 220, CD acknowledged William’s drawings of the pollen of one of the equal- …
- … styled plants, adding that the pollen resembled, in the small size of the grains, that of …
- … DAR 108. William may have made sketches of pollen from the pot of Chinese primrose he had …
From W. E. Darwin 8 July [1862]
Summary
WED reports on studying the pollen of grass and Valerian through his microscope.
| Author: | William Erasmus Darwin |
| Addressee: | Charles Robert Darwin |
| Date: | 8 July [1862] |
| Classmark: | Cornford Family Papers (DAR 275: 3) |
| Letter no: | DCP-LETT-3644F |
Matches: 5 hits
- … WED reports on studying the pollen of grass and Valerian through his microscope. …
- … been looking at it this morning I found pollen grains sticking to the treelike stigmas, …
- … of wheat by observing the stigma and pollen-tube under a high-powered microscope (see …
- … sketchbook (DAR 186: 43) contains a note dated 10 July 1862, describing pollen-masses …
- … and pollen-tubes of grasses. Valerian: Valeriana officinalis ). Lythrum : a genus of …
From William Erasmus Darwin 5 July [1869]
Summary
Observations on flies visiting Epipactis.
| Author: | William Erasmus Darwin |
| Addressee: | Charles Robert Darwin |
| Date: | 5 July [1869] |
| Classmark: | DAR 162: 100 |
| Letter no: | DCP-LETT-6816 |
Matches: 9 hits
- … ants I send. in one flower a single pollen mass was hanging down out of position, as if …
- … the ant was sucking hard away and the pollen masses were behind him in the channel of the …
- … flies (one of which I send without the pollen masses) crawl into some flowers that were …
- … they could turn round just underneath the pollen masses or anther without touching them. …
- … the lip (i.e. not backing) with the pollen masses attached to his back (this is the fly I …
- … I am nearly sure sure was the remains of the pollen masses on his back in just the same …
- … bottle to catch him. on one flower I saw the pollen masses sticking to an upper petal, in …
- … sticking across a flower which drew out the pollen masses with it; I brought it away as …
- … at, and in which there were no traces of pollen masses sticking to them or protruding ; I …
From W. E. Darwin 1 August 1862
Summary
WED has been collecting Lythrum plants. Numerical proportions of the three forms.
| Author: | William Erasmus Darwin |
| Addressee: | Charles Robert Darwin |
| Date: | 1 Aug 1862 |
| Classmark: | DAR 162: 90 |
| Letter no: | DCP-LETT-3675 |
Matches: 7 hits
- … dated 1 August 1862, of the two sets of pollen grains from the long and short stamens of …
- … of course I have made some hideous mistake) when the pollen is ripe and the anthers are …
- … opening, the filament is crimson and the pollen green— in these 27 plants …
- … the filaments were crimson and the pollen green in all the long stamens (only of course of …
- … was not a single red filament or green pollen to be seen—and I looked tolerably carefully …
- … through them all. I have looked at the two pollen of the Lp, and drawn and measured them …
- … is also difference I think between the pollens of the different kinds, but you will see …
From W. E. Darwin [April–May 1865]
Summary
Sends camera outlines of pollen. Thinks the red longstyled ones are more sterile than the yellow.
| Author: | William Erasmus Darwin |
| Addressee: | Charles Robert Darwin |
| Date: | [Apr–May 1865] |
| Classmark: | Cornford Family Papers (DAR 275: 20) |
| Letter no: | DCP-LETT-4506F |
Matches: 4 hits
- … Sends camera outlines of pollen. Thinks the red longstyled ones are more sterile than the …
- … Southampton Monday. My Dear Father, I enclose Camera outlines of the 3 sorts of pollen. …
- … I think the pollen of the red Longstyled & of the yellow Longstyled are as nearly of the …
- … difference in Primula ’ . William drew the pollen of these plants using a camera lucida …
From W. E. Darwin [19 May 1864]
Summary
Sends specimens of Menyanthes with observations and drawings [see Forms of flowers, p. 115].
| Author: | William Erasmus Darwin |
| Addressee: | Charles Robert Darwin |
| Date: | [19 May 1864] |
| Classmark: | DAR 110: B43–7 |
| Letter no: | DCP-LETT-4502 |
Matches: 7 hits
- … which I send in tin case. Also drawings of pollen & anthers. The long styled had decidedly …
- … these were William’s measurements of pollen diameters in an unknown unit; he presumably …
- … No relevant correspondence or additional pollen sketches have been found, but in Forms of …
- … with the camera many drawings of the pollen-grains’. CD noted the variability of stamen …
- … For William’s drawings of anthers and pollen, see enclosures 1 and 2. CD noted William’s …
- … added by CD, shows that the ratio of the diameter of pollen from short-styled flowers …
- … to the diameter of pollen from long-styled flowers is 100 to 84.2 (see Forms of flowers , …
From W. E. Darwin 18 April 1864
Summary
CD is right about variability [of Pulmonaria]. Encloses observations and diagrams of additional plants.
| Author: | William Erasmus Darwin |
| Addressee: | Charles Robert Darwin |
| Date: | 18 Apr 1864 |
| Classmark: | DAR 110: A77–81b |
| Letter no: | DCP-LETT-4466 |
Matches: 7 hits
- … in some cases than others. I measured the pollen in this shorter filamented one, & as you …
- … the division in the petals. I measured the pollen of two sets of Long & shorter styled and …
- … and always smaller than the short styled pollen. I did not measure the stigmas again as it …
- … reaching up to base of division of sepals pollen in each case exactly same size Some of …
- … to rather above their tips Measured the pollen in longest & shortest styled Long styled …
- … William’s two drawings. On the difference in pollen sizes for Pulmonaria angustifolia and …
- … at their original size. The sketches of pollen grains are all reproduced at 45 per cent of …
DCP-LETT-4427
Summary
[Outline sketches of pollen from short- and long-styled plants of Oxalis sinensis.]
| Author: | William Erasmus Darwin |
| Addressee: | Charles Robert Darwin |
| Date: | |
| Classmark: | DAR 108: 88 |
| Letter no: | DCP-LETT-4427 |
Matches: 1 hit
- … Outline sketches of pollen from short- and long-styled plants of Oxalis sinensis . ] …
From W. E. Darwin [24 April 1877?]
Summary
Sends notes made in June 1867, on Rhamnus catharticus and R. lanceolatus. Encloses diagrams and measurements relating to pollen size in R. lanceolatus.
| Author: | William Erasmus Darwin |
| Addressee: | Charles Robert Darwin |
| Date: | [24 Apr 1877?] |
| Classmark: | DAR 109: A44, A71–6 |
| Letter no: | DCP-LETT-10343 |
Matches: 4 hits
- … Encloses diagrams and measurements relating to pollen size in R. lanceolatus . …
- … equal 14 of L— pistilled therefore L— pistilled pollen grains the largest. therefore 10 …
- … p— diameters = L— p—d diamet ∴ L— pistilled pollen are largest 1.1 I am … judge. 2.2] …
- … I enclose diagram & measurements shewing pollen grains in L-pistilled Rh. Lanceolata to be …
From W. E. Darwin 20 June [1866]
Summary
Thinks Rhamnus is a case of a dimorphic plant that has become dioecious.
| Author: | William Erasmus Darwin |
| Addressee: | Charles Robert Darwin |
| Date: | 20 June [1866] |
| Classmark: | DAR 109: A77 |
| Letter no: | DCP-LETT-5128 |
Matches: 4 hits
- … his research on Primula , CD had observed that pollen-grains from short-styled forms were …
- … as you say at first, but I found that the pollen of long pistilled male was the largest, …
- … very remarkable’ observation that larger pollen-grains were produced in male flowers with …
- … plants tended to produce larger pollen-grains in flowers with shorter pistils, but that …
From W. E. Darwin 4 May [1863]
Summary
Sends observations on [Anchusa] plants from Isle of Wight.
| Author: | William Erasmus Darwin |
| Addressee: | Charles Robert Darwin |
| Date: | 4 May [1863] |
| Classmark: | DAR 110: 62 |
| Letter no: | DCP-LETT-4139 |
| letter | (30) |
| Darwin, C. R. | (30) |
| Darwin, C. R. | (30) |
| Darwin, W. E. | (30) |
Forms of flowers
Summary
Darwin’s book The different forms of flowers on plants of the same species, published in 1877, investigated the structural differences in the sexual organs of flowers of the same species. It drew on and expanded five articles Darwin had published on the…
Matches: 15 hits
- … male flowers on separate plants) and also noted that their pollen differed in size and shape. He …
- … of Primrose & Cowslip with short pistils & large-grained pollen are rather more fertile …
- … of my experiments lead me to suspect that the large-grained pollen suits the long pistils & the …
- … I think I have made out their good or meaning clearly. The pollen of A is fitted for stigma of B …
- … both terms referred to the fertilisation of one form with pollen from the same form. At this late …
- … two forms and that one of these was absolutely sterile with pollen from the same form, while the …
- … explained to Gray, ‘ I have lately been putting the pollen of the two forms on the division of the …
- … me as truly wonderful, that the stigma distinguishes the pollen; & is penetrated by the tubes of …
- … he told Hooker, ‘ In function, but not in appearance, the pollen of these two forms, as tested by …
- … is so frequent in truly hermaphrodite groups; namely the pollen & stigma of each flower being …
- … of the plant, with dotted lines indicating which pollen must be applied to each stigma to produce …
- … He told Gray in October 1865 that with respect to its own pollen, the long-styled form was …
- … plants raised from Dimorphic species fertilized by their own pollen, are themselves generally …
- … in a few specimens. It is necessary to compare size of pollen grains & state of stigma ’. …
- … ‘I will rank no plant as dimorphic without comparing pollen-grains & stigmas’. When Hermann …
Charles Harrison Blackley
Summary
You may not have heard of Charles Harrison Blackley (1820–1900), but if you are one of the 15 million people in the UK who suffer from hay fever, you are indebted to him. For it was he who identified pollen as the cause of the allergy. Darwin was…
Matches: 11 hits
- … fever, you are indebted to him. For it was he who identified pollen as the cause of the allergy, and …
- … 5 July 1873 Darwin wrote again, saying: ‘The power of pollen in exciting the skin & mucous …
- … changes in his own symptoms, that he was able to single out pollen as the only credible cause. …
- … He also experimented with fresh, dry and extracts of pollen, administered to his nose, mouth, eyes …
- … writes: Perhaps where grass is cut & dried; some pollen of the entomophilous division …
- … was fascinated by Blackley’s experiments testing whether pollen could be carried large distances in …
- … p. 5). Darwin gave a further example of how coniferous pollen could be carried for hundreds of miles …
- … with carbolic acid to deter insects. He concluded that in pollen seasons much higher levels were …
- … from hay fever in large cities far away from sources of pollen. In his later work, possibly …
- … Blackley tried to find out the smallest amount of pollen that would initiate and maintain the …
- … recommending spending summers in suitable locations to avoid pollen. But his lasting contribution …
Cross and self fertilisation
Summary
The effects of cross and self fertilisation in the vegetable kingdom, published on 10 November 1876, was the result of a decade-long project to provide evidence for Darwin’s belief that ‘‘Nature thus tells us, in the most emphatic manner, that she abhors…
Matches: 20 hits
- … flowers and the physiological effects of different forms of pollen. Although many plants that Darwin …
- … many of these were nevertheless fertile with their own pollen. He set out to compare several …
- … of the young plants when raised from a pistil fertilized by pollen from the same flower, & from …
- … that Darwin would confirm that this poppy shed its pollen immediately after the flower opened, …
- … since even those flowers to which he applied foreign pollen had probably already been self …
- … on which he commented, ‘This complete infertility with own pollen could hardly have remained …
- … you w d care, is that a great excess of, or very little pollen produced not the least difference …
- … On the other hand seeds from this plant, fertilised by pollen from the same flower, weigh less, …
- … beginning to suspect that the insects which could transfer pollen in sweet peas simply did not exist …
- … mignonette ( Reseda odorata ) was absolutely sterile with pollen from same plant in spite of the …
- … there sh d be some difference in ovules & contents of pollen-grains (for the tubes penetrate …
- … the same plant!’ ( To J. D. Hooker, 21 May [1868] ) Pollen tubes, or rapidly elongating vegetative …
- … ovary of a flower; they are triggered to elongate when the pollen touches the stigmatic surface. …
- … at the lessened fertility when he pollinated plants using pollen from other plants of the same …
- … the early part of the flowering season quite sterile with pollen from the same plant, though fertile …
- … as adults forever fixed in close proximity to others, so pollen from widely separated flowers could …
- … stylar forms of flowers, Darwin had referred to unions where pollen from one form had been applied …
- … that some forms were absolutely sterile with their own pollen while others had varying degrees of …
- … Ernst Haeckel, ‘It is really wonderful what an effect pollen from a distinct seedling plant which …
- … forms of flowers that showed sterility could exist when pollen from one form was applied to the same …
A fly on the flower: From Hermann Müller, 23 October 1867
Summary
In March 1867, Hermann Müller, a young teacher of natural sciences at a provincial Realschule (a type of secondary school that emphasised the natural sciences) in Lippstadt in the Prussian province of Westphalia, sent Darwin two papers on the mosses of…
Matches: 4 hits
- … order to observe their adaptations for collecting nectar and pollen. A letter he wrote in October …
- … of the hoverfly mouthparts that are specially adapted for pollen eating. Müller’s discovery seemed …
- … as pseudotracheae), which were the perfect size for holding pollen grains. He further noted, having …
- … in different species, depending on the size of the pollen eaten by each type of fly. It is amazing …
Floral Dimorphism
Summary
Sources|Discussion Questions|Experiment Floral studies In 1877 Darwin published a book that included a series of smaller studies on botanical subjects. Titled The different forms of flowers on plants of the same species, it consisted primarily of…
Essay: Evolutionary teleology
Summary
—by Asa Gray EVOLUTIONARY TELEOLOGY When Cuvier spoke of the ‘combination of organs in such order that they may be in consistence with the part which the animal has to play in Nature,’ his opponent, Geoffroy St.-Hilaire, rejoined, ‘I know nothing of…
Matches: 14 hits
- … meaning. One good illustration of it is furnished by the pollen of flowers. The seeming waste of …
- … ’ which every one has heard of. Myriads upon myriads of pollen-grains (each an elaborate organic …
- … a violet, in which there are not many times more grains of pollen produced than there are of seeds …
- … other flowers also, provided with a large surplus of pollen, and endowed (as the others are not) …
- … to certain insects, which are thereby induced to convey this pollen from blossom to blossom, that it …
- … of which are committed to insects, the likelihood that much pollen may be left behind or lost in the …
- … in orchis-flowers is accounted for by the fact that the pollen is packed in coherent masses, all …
- … against it when it sucks nectar from the flower, and so the pollen will be bodily conveyed from …
- … case, that of pine-trees, the vast superabundance of pollen would be sheer waste if the intention …
- … ’ as the means, no one is entitled to declare that pine-pollen is in wasteful excess. The cheapness …
- … involved in similar difficulty. The superabundance of the pollen of pine-trees above referred to, …
- … In the analogous instance of willows a diminished amount of pollen is correlated with direct …
- … difference in the conveyance would reduce the quantity of pollen produced. It is, we know, in the …
- … work and material; but why should it begin to produce less pollen? But this is as nothing compared …
Orchids
Summary
Sources|Discussion Questions|Experiment A project to follow On the Origin of Species Darwin began to observe English orchids and collect specimens from abroad in the years immediately following the publication of On the Origin of Species. Examining…
From morphology to movement: observation and experiment
Summary
Darwin was a thoughtful observer of the natural world from an early age. Whether on a grand scale, as exemplified by his observations on geology, or a microscopic one, as shown by his early work on the eggs and larvae of tiny bryozoans, Darwin was…
Hermann Müller
Summary
Hermann (Heinrich Ludwig Hermann) Müller, was born in Mühlberg near Erfurt in 1829. He was the younger brother of Fritz Müller (1822–97). Following the completion of his secondary education at Erfurt in 1848, he studied natural sciences at Halle and Berlin…
Orchids
Summary
Why Orchids? Darwin wrote in his Autobiography, ‘During the summer of 1839, and, I believe, during the previous summer, I was led to attend to the cross-fertilisation of flowers by the aid of insects, from having come to the conclusion in my…
Matches: 5 hits
- … puzzles me.— The Fly-Ophrys seems hardly ever to get its pollen masses moved at all, & the …
- … agency—another part, namely the natural falling out of the pollen-masses, being adapted for self …
- … in which I ask for information on what kinds of moths the pollen-masses of Orchids have been found …
- … Hooker, ‘ I shall never rest till I see a Catasetum eject pollen-masses, & a Mormodes twist its …
- … not only because of its remarkable ability to eject its pollen masses like a catapult, but also …
The evolution of honeycomb
Summary
Honeycombs are natural engineering marvels, using the least possible amount of wax to provide the greatest amount of storage space, with the greatest possible structural stability. Darwin recognised that explaining the evolution of the honey-bee’s comb…
Fool's experiments
Summary
‘I love fools' experiments. I am always making them’, was one of the most interesting things the zoologist E. Ray Lankester ever heard Darwin say. ‘A great deal might be written as comment on that statement’, Lankester later recorded, but he limited…
Matches: 1 hits
- … to Lankester involved placing under a bell jar some pollen from a male flower together with, but …
Darwin in letters, 1864: Failing health
Summary
On receiving a photograph from Charles Darwin, the American botanist Asa Gray wrote on 11 July 1864: ‘the venerable beard gives the look of your having suffered, and … of having grown older’. Because of poor health, Because of poor health, Darwin…
Matches: 4 hits
- … whereby each form achieved the highest fertility only with pollen from the other two forms. The …
- … collecting and measuring flower parts, drawing pictures of pollen-grains, stigmas, and anthers, and …
- … writing on 14 April [1864] , ‘I can do as much pollen work as ever you like’. Comments on William’s …
- … Crüger confirmed both his observation of Catasetum pollen adhering to a humble-bee’s back, …
What is an experiment?
Summary
Darwin is not usually regarded as an experimenter, but rather as an astute observer and a grand theorist. His early career seems to confirm this. He began with detailed note-taking, collecting and cataloguing on the Beagle, and edited a descriptive zoology…
Darwin in letters, 1862: A multiplicity of experiments
Summary
1862 was a particularly productive year for Darwin. This was not only the case in his published output (two botanical papers and a book on the pollination mechanisms of orchids), but more particularly in the extent and breadth of the botanical experiments…
Species and varieties
Summary
On the origin of species by means of natural selection …so begins the title of Darwin’s most famous book, and the reader would rightly assume that such a thing as ‘species’ must therefore exist and be subject to description. But the title continues, …or…
Scientific Practice
Summary
Specialism|Experiment|Microscopes|Collecting|Theory Letter writing is often seen as a part of scientific communication, rather than as integral to knowledge making. This section shows how correspondence could help to shape the practice of science, from…
Matches: 1 hits
- … fertility of orchids he has self-pollinated and crossed with pollen of other species. …
Scientific Networks
Summary
Friendship|Mentors|Class|Gender In its broadest sense, a scientific network is a set of connections between people, places, and things that channel the communication of knowledge, and that substantially determine both its intellectual form and content,…
Matches: 3 hits
- … He discusses how dipterous insects are adapted to eating pollen rather than only to sucking nectar. …
- … flowers. One is ripening. Dissection of the other shows the pollen accomplishes fertilisation …
- … interpretation of Acropera pollination is ingenious. Pollen-tubes of some cleistogamous flowers …
Darwin in letters, 1877: Flowers and honours
Summary
Ever since the publication of Expression, Darwin’s research had centred firmly on botany. The year 1877 was no exception. The spring and early summer were spent completing Forms of flowers, his fifth book on a botanical topic. He then turned to the…
Matches: 4 hits
- … . ‘I will rank no plant as dimorphic without comparing pollen-grains & stigmas’, Darwin …
- … and painstaking measurements of the size and number of pollen-grains, Darwin compared the fertility …
- … especially with the aid of insects: the size and shape of pollen-grains, the position of stigmatic …
- … life to which all organisms are subjected, by producing both pollen and seeds’ ( Forms of flowers …
A tale of two bees
Summary
Darwinian evolution theory fundamentally changed the way we understand the environment and even led to the coining of the word 'ecology'. Darwin was fascinated by bees: he devised experiments to study the comb-building technique of honey bees and…
Matches: 1 hits
- … is, depressing the keel so that the mechanism which caused pollen to be deposited on the bee would …
