376 



A NGIOSPERMAE—DICO TYLEDONES 



flowering, secretes a thin layer of nectar that gives a yellowish appearance to the 

 whole inflorescence. The stamens and pistil are rarely developed normally : either 

 the stamens are developed, while the style remains so short that the stigma hardly 

 projects beyond the nectary, or the style is long, and 1-3 or all four of the 

 stamens are reduced. Automatic self-pollination is therefore rendered very difficult. 

 Kerner, however, says that it may take place in the hermaphrodite flowers, which 

 are protogynous and therefore primarily adapted for cross-poUination, for the stigma 

 remains receptive till the anthers are ripe, and is brought into contact with them 

 by elongation of the style. 



Visitors. — Herm. Miiller saw a hover-fly (Xanthogramma citrofasciata Deg.), 

 and Lindman noticed flies on the DovreQeld. 



Herm. Miiller observed 3 Lepidoptera and 6 flies in the Alps (' Alpenblumen,' 

 pp. 223-4); Loew saw the hover-fly Melithreptus scriptus L. in Switzerland 

 ('Beitrage,' p. 55); and MacLeod noticed a beetle and 5 flies in the Pyrenees 

 (Bot. Jaarb. Dodonaea, Ghent, iii, 1891, p. 433). 



Plateau observed flies (Calliphora, Musca, Scatophaga, and Syritta pipiens Z.) 

 and small Hymenoptera in Belgium. 



Fig. 117. Alchefnilta vulgaris, L. (after Herm. Muller). (i) Flower with normal stamens and 

 a short style, seen directly from above. (2) The same, .seen obliquely from above. (3) Flower with one 

 normal and three vestigial stamens, and normal style; seen obliquely from above. {4) Flower with all 

 the stamens vestigial, and well-developed style, a, epicalyx ; 3, calyx ; c, stamens ; c', vestigial stamens ; 

 rf, stigma ; *, nectary. 



In Dumfriesshire, a long-tongued bee, a Tenthredinid, 2 Empids, several other 

 flies, and 2 Lepidoptera were recorded (Scott-Elliot, ' Flora of Dumfriesshire,' p. 59). 

 In spite of repealed watching, I have never observed any insects on the flowers. 



902. A. alpina L., 903. A. fissa Schum., and 904. A. pentaphyllea L. — 



Hermann Muller (' Alpenblumen,' pp. 222-3) states that these species agree with 

 A. vulgaris and Sibbaldia procumbens, as regards their flower mechanism, the 

 distribution of sexes, and the degeneration of various organs. Trimerous and 

 pentamerous flowers are not infrequent. (Cf. Fig. 118.) 



Visitors. — Herm. Muller saw small Muscids, beetles, ants, and Ichneumonids. 



MacLeod observed (on A. alpina) 2 beetles and 4 flies in the Pyrenees (Bot. 

 Jaarb. Dodonaea, Ghent, iii, 1891, p. 433). Loew noticed a small bee (Sphecodes 

 gibbus L. 5), skg., in the Berlin Botanic Garden. 



905. A. arvensis Scop. — The very insignificant green flowers of this species 

 are associated in small dense sessile glomerate cymes, but in spite of this are extremely 

 inconspicuous. Kirchner (' Flora v. Stuttgart,' p. 449) says there is a nectary, but it 

 is green and non-functional. The single stamen slants obliquely inwards, so that its 

 anther is situated above the stigma, and automatic self-pollination is inevitable. 



