216 MR. I. H. BURKILL ON SOME VARIATIONS IN 
On some Variations in the Number of Stamens and Carpels. By 
I. H. Burkitt, B.A., F.L.S, Gonville and Caius College, 
Cambridge. 
[Read 17th January, 1895.] 
Tue capability of varying is admittedly a general property of all 
living organisms ; but of how variation is affected by forces other 
than natural selection we know but little. In beginning this 
series of observations, commenced at the suggestion of Mr. J. 
C. Willis, I have had in view principally the object of ascer- 
taining why stamens and carpels are often reduced in number. 
The literature bearing on this subject is much scattered, and 
principally turns upon the question of unfavourable conditions 
causing the total—not partial—disappearance of the andrecium 
or gynecium. To what degree do we understand how conditions 
affect the sexual organs in the individual, not the race? The 
elaborate experiments of H. Hoffmann’, F. Heyer’, C. Fisch °, and 
Düsing* on the sex of the Hemp, and of Heyer’ on Mercurialis 
annua, have shown that here, for any variety, the proportion of 
male to female plants is the same under all conditions. Clos P 
too, says that dwarfing does not affect the sex of the plant; in 
other words, the sex is, as Heyer says, present in the seed. But, 
on the other hand, Forsberg’ finds that the sex of the J uniper 
is influenced by the nature of the place in which it grows—the 
more inclement the spot, the greater the percentage of male 
plants. A similar result Hoffmann ° gets with Spinacia, Lychnis 
? “ Riickblick auf meine Variations-Versuche yon 1855-1880.” Bot. Zeitung, 
xxxix. p. 381 (1881). 
? “Das Zahlenverhältniss d. Geschlechter.” Deutsche landwirt. Presse, 
xiii. 1886, p. 163; fide Just's Jahresbericht, 1886, p. 814. 
® “ Ueber die Zahlenverhiiltnisse d. Geschlechter beim Hanf.” Berichte d. 
deutschen bot. Gesellschaft, v. p. 136 (1887). 
* “ Die experimentale Prüfung d. Theorie v. d. Regulierung d. Geschlechis- 
verháltnisses"  Jenaische Zeitschrift, xix. p. 108 (1885). 
5 “Untersuchungen ü. d. Verháültniss d. Geschlechtes bei einháusigen u. 
zweiháusigen Pflanzen." Inaug. Diss. Halle, 1883. Reviewed, Bot. Centralblatt, 
xv. p. 5. 
6 “ Du nanisme dans le règne végétal" Mém. Acad. Toulouse, 9™° série, 
i. p. 391 (1889). 
7 “Ueber d. Geschlechtsverthe 
blatt, xxxiii. p. 91 (1888), 
* “Ueber Sexualität,” 
ilung bei J uniperus communis.” Bot. Central- 
Bot. Zeitung, 1885, xliii, p. 145. 
