' 



610 ANGIOSPERMAEDICOTYLEDONES 



are beset internally with stigmatic papillae. These branches are relatively broad and 

 long, and ultimately bend outwards from one another till they become reflexed. The 

 yellow pollen is not mealy and not readily dispersed, but clumps of it remain clinging 

 to the top of the anther-cylinder. The florets are nectarless, and the annular nectary 

 at the base of the style is absent. 



1444. A. borealis Pall. (Abromeit, ' Bot. Ergeb. von Drygalski's Gronlands- 

 exped.,' pp. 64-5.) This very variable species was several times collected by 

 Drs. von Drygalski and Vanhoflen in Greenland. The colour of the involucral 

 bracts and corolla-lobes of male florets is often purple, but may be golden-yellow or 

 greenish-white. In many cases the heads are almost purely male or predominatingly 

 female, and either protogynous or protandrous. 



1445. A. Mutellina VOL This species, like A. glacialis, was investigated at 

 Zermatt by Kirchner (' Beitrage,' p. 69). It, too, belongs to class Po, with transition 

 to class An. The inflorescences are smaller, and their racemose arrangement also 

 tends to make them less conspicuous. A head usually consists of 8-16 golden- 

 yellow florets, of which the 5-8 marginal ones are female. Their stigmas mature 

 before the pollen of the hermaphrodite florets of the same head is available, so that 

 they are usually crossed by pollen from older heads, geitonogamously according to 

 Kerner. 



1446. A. Absinthium L. (Knuth, ' Bl. u. Insekt. a. d. nordfr. Ins.,' pp. 89-90.) 

 This species belongs to class Po with transition to class An. The numerous, almost 

 spherical heads (about 4 mm. in diameter) are closely crowded on the many switch-like 

 branches that are easily moved by the wind. The stem is more than a metre high. 

 The plant is rendered tolerably conspicuous by the yellow colour of the tiny florets, 

 of which about 50 are aggregated into a head. Each of them, including the 

 ovary, is only 2 mm. long. The stylar branches of the central female florets possess 

 a few sweeping-hairs at their tips, and when the pollen has been removed they roll 

 up into two circular coils that project beyond the corolla, and present their stigmatic 

 surfaces to alighting insects, by which they may be pollinated. Pollen-devouring 

 insects are now and then attracted to the plant by sight, though it is only moderately 

 conspicuous, and by its aromatic odour. 



Visitors. The following were recorded by the observers, and for the localities 

 stated. 



Knuth (Kiel), the hover-fly Syrphus ribesii ., po-dvg. (' Bloemenbiol. Bijdragen'). 

 Rossler (Wiesbaden), the moth Grapholitha pupillana CI. Schletterer (Tyrol), the 

 bee Andrena combinata Chr. 



1447. A. Dracunculus L. 



Visitors. Borgstette (Nassau) observed a po-dvg. hover -fly (Melanostoma 

 mellina Z.). 



1448. A. maritima L. (Knuth, ' Bl. u. Insekt. a. d. nordfr. Ins.,' p. 90.) 

 This species possesses an aromatic odour. The short-stalked ovoid heads are 

 easily moved by the wind. 



1449. A. vulgaris L. (Knuth, loc. cit.) The very small ovoid heads are 

 6 mm. long and 3 mm. broad. Each contains about 20 florets 4 mm. in length. 

 MacLeod gives a figure (Bot. Jaarb. Dodonaea, Ghent, v, 1893, p. 420). 



