. Handbook of flower pollination : based upon Hermann Mu?ller's work 'The fertilisation of flowers by insects' . Fertilization of plants. 378 ANGIOSPERMAE—DICOTYLEDONES to Warnstorf (Schr. natw. Ver., Wernigerode, xi, 1896), only the uppermost flowers of the capitula are female, as a rule, and are in a minority; the other flowers are male, often with an isolated hermaphrodite flower here and there between them. The anthers are yellow, and pendulous on long reddish filaments. The hermaphro- dite flowers possess but few stamens. The pollen-grains are of a dirty yellowish- white colour, rounded-p
. Handbook of flower pollination : based upon Hermann Mu?ller's work 'The fertilisation of flowers by insects' . Fertilization of plants. 378 ANGIOSPERMAE—DICOTYLEDONES to Warnstorf (Schr. natw. Ver., Wernigerode, xi, 1896), only the uppermost flowers of the capitula are female, as a rule, and are in a minority; the other flowers are male, often with an isolated hermaphrodite flower here and there between them. The anthers are yellow, and pendulous on long reddish filaments. The hermaphro- dite flowers possess but few stamens. The pollen-grains are of a dirty yellowish- white colour, rounded-polyhedral, smooth, up to 37 /i in diameter. Ludwig says that not infrequently there are variations in the colour of the stamens of different male flowers, from which the anthers hang down limply on long thin filaments. As a rule the anthers are yellow, and the filaments white ; but stocks also occur in which the filaments are red, and the anthers yellowish-red to red. In the female flowers the style and the large spreading stigma are red to wax-yellow or white. Visitors.—Herm, Miiller ('Fertilisation,' p. 236) saw a wasp (Odynerus parie- tum L. 5) settle on the flowers, flying away again after a short and profitless search. I noticed a hover-fly (Melanostoma mellina Z.), po-dvg., on the inflorescence. In Dumfriesshire a Tenthredinid and 2 hover-flies were recorded (Scott-Elliot, 'Flora of Dumfriesshire,' p. 61).. Fig. 119. Sangitisorba officinalis, L. (after Herm. Mullen. A. Flower seen directly from above. B. The same, seen from the side. C. The same, in longitudinal section. D. Single sepal, seen from within. (X 7) a, anther; br, bract; ca, receptacle; Ji, filament; gr, style; /;, drop of nectar: »;, nectary ; oi\ ovary ; s, sepal; si, stigma. 909. S. alpina Bunge.—In this species, as in Thalictrum aquilegiifolium, the filaments are claviform, and therefore shaken by the slightest breath of air, so that the pollen is scattered (Kerner, 'Nat. Hist. PI.,' II, p. 145). 25
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