COMPOSITAE 607 



1437. G. luteo-album L. (Warnstorf, Verb. bot. Ver., Berlin, xxxviii, 1896.) 

 Warnstorf says that the numerous narrow, tubular, female ray-florets of this species 

 mature their stigmatic branches before the few (8-10) hermaphrodite disk-florets open ; 

 and that they elongate after pollination so as once more to completely enclose the 

 stigmas. Geitonogamy is only possible between the inner female florets and the outer 

 hermaphrodite ones. The pollen-grains are yellow in colour, rounded, with long 

 spines, on an average 25 /* in diameter. 



Visitors. Herm. Miiller observed the following at Lippstadt ('Fertilisation,' 

 P- 324)- 



A. Diptera. Musctdae: 1. Lucilia, in large numbers; 2. Pollenia rudis F., 

 po-dvg. Syrphidae : 3. Melanostoma mellina Z., po-dvg. ; 4. Melithreptus scriptus 

 Z., do. B. Hymenoptera. (a) Apidae : 5. Halictus quadrinotatus Schenck $ and j, 

 skg. ; 6. Sphecodes gibbus Z., $ and 5, different varieties, also S. ephippius Z., skg. 

 (6) Sphegidae: 7. Ceropales maculatus F., skg.; 8. Pompilus viaticus Z., do. 



1438. G. sylvaticum L. (Knuth, ' Bl. u. Insekt. a. d. nordfr. Ins.,' p. 89; Kirchner, 

 ' Beitrage,' p. 66.) The elongated heads of this species are arranged in a spike, 

 and are but slightly conspicuous. Kirchner describes them as 5-6 mm. long, with a 

 diameter above of only i-|-2 mm. Each contains 60-70 female florets, and a few 

 (usually only 3-4) hermaphrodite ones. In both of these the corolla is 4 mm. in 

 length, and there is no difference in the form of the pistil : it contains one ovule, and 

 there is an annular nectary at the base of the style. The style of the female florets is 

 glabrous, and its two curved stigmatic branches, which are thin and moderately long, 

 spread out above the corolla-tube. The upper end of the style of hermaphrodite 

 florets is covered with sweeping-hairs. These brush out the pollen, and the two 

 stylar branches then diverge, so that the stigmatic papillae of their inner surfaces 

 become visible. 



As I observed in the North Frisian Islands, either automatic self-pollination or 

 geitonogamy may now occur, for the spinose pollen-grains still clinging to the 

 sweeping-hairs may fall upon the stigmas of the same or neighbouring florets. 



Visitors. A Muscid was recorded in Dumfriesshire (Scott-Elliot, 'Flora of 

 Dumfriesshire/ p. 92). 



1439. G. uliginosum L. (Knuth, ' Bl. u. Insekt. a. d. nordfr. Ins.,' p. 89 ; 

 Kirchner, 'Beitrage,' p. 66.) The heads of this species are of a rounded ovoid 

 shape, 1^-2 mm. in diameter above, and aggregated into crowded leafy clusters. 

 The individual florets are also only 1^-2 mm. long. Kirchner counted rather more 

 than 100 female florets, and usually 6 hermaphrodite ones in each head: I have 

 observed only about 30. The flower mechanism otherwise agrees with that of the 

 last species. 



According to Warnstorf (Verh. bot. Ver., Berlin, xxxviii, 1896), the tips of the 

 involucral bracts of the small heads project somewhat beyond the female ray-florets, 

 pressing their stigmatic branches inwards towards the pollen of the few hermaphrodite 

 florets, so as to effect geitonogamy. The pollen-grains are pale yellow in colour, 

 ellipsoidal, with spinose tubercles, about 25 /x long and 19 \x. broad. 



Visitors. Herm. Miiller observed the bee Sphecodes ephippius Z., skg. 



