218 MR. I. H. BURKILL ON SOME VARIATIONS IN 
perfoliatum is dependent on the time of the flowering period of 
the plant, and in Hyoscyamus niger, Linn., b. agrestis, Veit.”, is 
dependent on the position of the flower. Raunkjaer " observes 
that female flowers on Scabiosa succisa, L., are more common in 
Denmark than in Würtemberg. 
Androdiecism and andromonecism are attributable to similar 
causes. Hermann Müller" observed the abortion of the carpels 
in the Alps, and attributes it to insufficient nutrition. 
But now coming to cases where the sexual organs of both 
sexes are present, but vary in number, we find very little 
information. Changes in the proportion of stamens to carpels 
have been noted in Stratiotes to have some relation to climate. 
Goethardt"" has observed in Pavonia that plants of warmer 
localities have more stamens in their flowers than those of colder 
places ; but this characteristic exhibited a tendency to inheritance. 
For in seed grown at Gottingen, obtained from Breslau, Leipzig, 
Buda-Pest, aud Palermo, the following average numbers of 
stamens were obtained:— 25:25, 29, 304, and 32:1 respectively. 
Beyond this there are but few faets recorded; and the observa- 
tions contained in this paper were commenced with a view to fill 
in part this gap in our knowledge. It is obvious that they have 
considerable bearing upon questions connected with gyno- and 
andro-diecism and -monecism, and on the origin of diccism 
and diclinism. 
From the observations of many observers, cleistogamy is caused 
by the following influences :—according to Warming”, by cold 
(Caryophyllacee); to J. Scott " (Acanthacex), Michalet ” 
(Viola), Torrey and Gray” (Helianthemum), and Hoffmann ° 
Papaver), by poor soil ; to Eggers ?', by unfavourable atmospheric 
881) Weitere biologisehe Mittheilungen.” Bot. Centralblatt, viii. p. 89 
1€ * Nogle Jagttagelser over Planter med forskjelligformede Blomster.” 
Bot. Tidsskrift, xvii. p. 238 ; fide Just’s Jahresbericht, 1889, p. 554. 
17 “ Die Variabilität d. Alpenblumen.” Kosmos, vii. p. 441 (1880). 
^* “ Beiträge zur Kenntniss d. Malvaceen-Androecium." Bot. Zeitung, xlviii. 
p. 990 (1890). 19? Loe. cit. 
2° * Dimorphism in Zranthemum.” Journ. of Bot. x. 1872, p. 161. 
21 “Sur la Floraison des Viola de la Section N omimium, de I’ Oxalis acetosella 
et du Linaria spuria?” Bull. Soc. Bot. de France, vii. 1860, p. 465. 
22 A Flora of North America, vol. i. p. 151. New York, 1838-40. 
23 ** Culturversuche ü. Variation." Bot. Zeitung, xlii. p. 226 (1884). 
24 * Kleistogamie einiger West-indischer Pflanzen." Bot. Centralblatt, viii. 
p. 97 (1881). 
