COMPOSITAE 605 



1433. A. dioica Gaerln. (=Gnaphalium dioicum Z.). (Hildebrand, 'U. d. Ge- 

 schlechtsverhalt. b. d. Compositen,' pp. 40-2, Taf. Ill, Figs. 26-32 ; Herm. Muller, 

 ' Alpenblumen,' p. 436; Lindmann, 'Bidrag till Kanned. om Skandin. Fjellvaxt. 

 Blomn. o. Befrukt.'; Kerner, 'Nat. Hist. PI./ Eng. Ed. 1, II; Kirchner, 'Flora 

 v. Stuttgart,' p. 703; Knuth, ' Bloemenbiol. Bijdragen.') This species is dioecious. 

 The white or rose-coloured involucral bracts render the heads conspicuous. The 

 female florets are filiform, the male ones tubular; both kinds contain nectar. 

 Hildebrand states that the ovary of male florets contains no ovule, while the 

 style divides into two short blunt branches, devoid of stigmatic papillae ; on the 

 other hand, the whole upper part of the style is covered with sweeping-hairs, those 

 at the tip being longest. The corolla, tubular below, ends in a bell with somewhat 

 recurved lobes. The filaments are irritable, and curve when touched. In this way 

 the anther-cylinder is retracted, so that pollen protrudes from its upper end. The 

 corolla-tube of female flowers is long and narrow. The style projects beyond it, 

 and the branches of this are externally covered with short hairs at their tips only, 

 while their inner surfaces possess a line of stigmatic papillae on either side. 



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

 stated. 



Lindmann (Dovrefjeld), a few Lepidoptera. Herm. Muller (Alps), a hover-fly, 

 a fossorial wasp, and 9 Lepidoptera. Knuth (Tondern), a po-dvg. hover-fly (Eristalis 

 tenax Z.) and a butterfly, skg. MacLeod (Pyrenees), 2 Muscids (Bot. Jaarb. Dodonaea, 

 Ghent, iii, 1891, p. 363). 



1434. A. margaritacea R. Br. (=Gnaphalium marginatum Z.). 

 Visitors. I observed (12.9/97), 2 po-dvg. hover-flies (Eristalis tenax Z., and 



E. intricarius Z.), 2 beetles (Coccinella quinquepunctata Z., and C. qualtuordecim- 

 punctata Z.), and Thrips. 



1435. A. alpina Gaertn. (=Gnaphalium alpinum Z.). This northern species 

 is dioecious. According to Hartman (' Handbok i. Skand. Flora,' p. 7), Laestadius 

 found male plants in 1842. Vahl, Lange, and Warming do not know of any such, 

 but on the contrary suppose the species to be parthenogenetic, as it has been 

 observed to set fruits in various localities. 



The specimens collected by Dr. von Drygalski's Greenland expedition were 

 all female (Abromeit, ' Bot. Ergeb. von Drygalski's Gronlandsexped.,' p. 65). 



According to Juel (' Vergleich. Untersuch. u. typische u. parthenogenet. Fortpfl. 

 b. d. Gatt. Antennaria,' pp. 12-13), male stocks are extremely rare in Lapland and 

 Norway: their florets usually contain a small quantity of functionless pollen or 

 none at all. Reproduction is parthenogenetic. Juel (op. cit, p. 14) considers that 

 the existence of male stocks is due to atavism : but he also thinks it possible 

 that A. alpina may really be a hybrid, perhaps the result of crossing between 

 A. dioica Gaertn. and A. monocephala DC. 



448. Gnaphalium L. 



Ray-florets female, filiform, in several series; disk-florets hermaphrodite and 

 tubular ; the tip of the style covered with tufted sweeping-hairs. 



1436. G. Leontopodium L. ( = Leontopodium alpinum Cass.). (Herm. Muller, 

 'Alpenblumen,' pp. 434-6; Kerner, 'Nat. Hist. PI.,' Eng. Ed. 1, II; MacLeod, 



