578 ANGIOSPERMAE—DICOTYLEDONES 



(Flanders), Apis, a short-tongued bee, and 3 flies (Bot. Jaarb. Dodonaea, Ghent, vi, 

 1894, p. 373). Friese (Fiume), the bee Andrena taraxaci Gir. Schneider (Arctic 

 Norway), 2 humble-bees — Bombus hypnorum Z., and B. terrester L. (Tromso Mus. 

 Aarsh., 1894). 



417. Petasites L. 



Dioecious-polygamous. Male florets with a bell-shaped regularly five-toothed 

 limb to the corolla : female florets filiform, with the corolla-limb obliquely truncated. 

 The stylar branches, especially in male florets, covered externally with sweeping- 

 hairs; papillose on their inner surfaces in female florets. Kerner points out that 

 sexually differing stocks also differ from one another in appearance. In one kind 

 of plant there are numerous pseudo-hermaphrodite pollen-florets in the disk, and 

 a small number of female flowers round the margin ; in the other kind the relative 

 numbers are reversed. 



1321, P. officinalis Moench ( = P. vulgaris Des/., Tussilago Petasites Z., the 

 so-called hermaphrodite plant, and T. hybrida Z., the female plant). (Hildebrand, 

 ' U. d. Geschlechtsverhalt. b. d. Compositen,' pp. 35-40, Taf. IV, Figs, i-i 9 ; Kirchner, 

 'Flora v. Stuttgart,' p. 690; Kerner, 'Nat. Hist. PL,' Eng. Ed. i, II ; Herm. MuUer, 

 ' Weit. Beob.,' Ill, p. 92 ; MacLeod, Bot. Jaarb. Dodonaea, Ghent, v, 1893, p. 411 ; 

 Knuth, ' Bloemenbiol. Bijdragen ' ; Warnstorf, Verb. bot. Ver., Berlin, xxxviii, 1896.) — 

 The florets of this species are of a dull-purple colour, rarely pale-red, or nearly 

 white. The plant occurs in two forms quite different from one another in appearance. 

 Kerner says that in one of these there are numerous pseudo-hermaphrodite pollen- 

 florets in the disk, and a smaller number of purely female ray-florets ; in the other 

 form the relative numbers are reversed. Male stocks possess shorter peduncles 

 and crowded inflorescences; the 22-38 florets in a head, according to Kirchner, 

 are either all similar and nectariferous, or there may be as many as three herma- 

 phrodite florets among them. The ovule is usually vestigial ; the style presents 

 a club-shaped somewhat compressed thickening under its branches, which are beset 

 with sweeping-hairs. The stylar branches curve away a Utile from each other, 

 and are covered externally with short sweeping-hairs ; they are devoid of stigmatic 

 papillae internally. The corolla of the male florets is tubular below, expanding 

 above into a bell with five recurved lobes. 



For the female plants, Kirchner describes the inflorescences as taller but less 

 dense. Each head contains about 140 florets, of which 1-3 central ones are male. 

 The female florets are nectarless and show no trace of stamens. Their corolla is 

 in the form of a long narrow tube, which is produced into two lips, one narrow 

 and the other broader. The style is filiform and smooth ; its two branches are 

 covered with short hairs externally, and beset with stigmatic papillae internally. 

 The 1-3 male florets in the centre possess a bifurcated style, but slightly if at all 

 thickened, and covered with sweeping-hairs. The annular nectary secretes abundantly ; 

 the anthers are vestigial and produce no pollen. 



Burkill observed only male inflorescences on the Yorkshire coast (' Fertlsn. 

 of Spring Fls.'). At Neu-Ruppin (Brandenburg) the species also only occurs, 

 according to Warnstorf, in one form bearing pseudo-hermaphrodite infertile pollen- 

 florets. The stylar branches, which are densely covered with papillose sweeping- 



