Jan. 13, 1876] 



NA TURE 



211 



( Vcnessa UrticcE) was attracted by the bright colour of the 

 flowers, and inserted its proboscis into several of them, 

 possibly without touching stigma and anthers. 



Of Daphm striata 1 had not yet the opportunity of ob- 

 serving the fertilisers ; but completely white flowers 

 of this species, which I found in the pass of Strela, near 

 Davos, may be considered as confirming my supposition 

 that D. striata is adapted to crespuscular and nocturnal 

 Lepidoptera. 



2. Regarding Primula officinalis and villosa, no addi- 

 tional remarks are to be made. I have, however, observed 

 another Alpine species of Primula {P. integri/olia), which 





Figs. 76-81. Rhinanthus aUetiyrohfhus.* 

 flower. 



Fig. 76. — Lateral view of the 



is apparently adapted, like P. villosa, by the narrowness 

 of the entrance of its corolla-tube, to butterflies. And 

 with regard to some other species which inhabit higher 

 Alpine localities {P. lon^lflo7-a, and P. minima) I sup- 

 pose that they are in the same condition. Primula iti- 

 tegrifolia, which \ found frequently on the summits sur- 

 rounding the passes of Strela and Fluela, is dimorphic, 

 like most other species of this genus. Its sexual organs 

 are quite included, the stigma of the long-styled and the 

 anthers of the short-styled form occupying nearly the 

 centre, the anthers of the long-styled and th» stigma of 

 the short-styled form occupying the lower part (i^ mm. 

 above the ovary and 3 mm. above the ground) of the 

 corolla-tubes. (Compare Figs. 72 and 73, 74 and 75.) 

 Honey is secreted by the ovary in such quantity that it fills 

 up the lowermost part of the corolla-tube so far as nearly 

 to reach the stigma of the short-styled and the anthers 

 of the long-styled form. The corolla-tube being 10-17 mm. 

 long and about 2 mm. wide, its dimensions would allow 



Fig. 77. —The corolla viewed laterally. 



humble-bees also access to the honey ; but the entrance 

 to the corolla being contracted to i mre. (Fig. 71), no 

 other insect but a lepidopterous one woijld be enabled 



• All the figures are 3} times natural size. In all figurej : ca, calyx ; //, 

 upper petals, forming together the upper lip ; /'/' p' , low^r petals, forming 

 the lower lip ; n', longer stamens ; a'^, shorter stamens ; n, nectary ; cn>, 

 owy ; st, stigma ; e, usual entrance for the humble-bees ; <', minute opening 

 for the butterflies. The dotted line in Fig. 80 indicates the pith of the pro- 

 Doscis of sucking humble-bees ; the dotted line in Fig. 81 tie path of the 

 proboscis of butterflies. 



to insert its proboscis into the base of the flower and 

 reach the honey. On the other hand, the corolla is narrow 

 enough to force also the thin proboscis of a butterfly to 

 touch, when inserted, both the stigma and the anthers. 

 I do not doubt, therefore, that P. integrifolia is also cross- 

 fertilised by butterflies, although, from the unfavourable 

 state of the weather, I have had no opportunity of observing 

 its fertilisers. 



3. Rhinanthus alpinus last year attracted my atten- 

 tion only during the last days of my stay in the Alps, when 

 rainy weather prevented me from observing its fertilisers ; 



Fig. 78. 



FlG. 79. 



Fig. 80. 



Fig. 78. — Front view of the upper part of the corolla. Fig. 79. — The same 

 with the under lip removed. Fig. 80. — The upper part of the corolla, 

 longitudinally dissected, but all four anthers reversed. 



I concluded, solely from the structure of its flowers, that 

 it was adapted to butterflies. This year it was an object 

 of my continued attention ; and in a reg:on where Lepi- 

 doptera are predominant, but humble-bees are also very 

 frequent, near Tschuggen (1,900 to 2,000 m. above the 

 sea-level), Forno (1,800 m.), Valcava (1,500 m.), and St. 

 Gertrud, Sulden (r,8oo to 1,930 m.), I had large oppor- 

 tunities of directly observing its fertilisation by insects. 

 But 1 was greatly struck by the fact that in these localities 

 humble-bees visit its flowers far more frequently than 

 butterflies. The number of visits which Bombus alticola, 

 Kriechb. ^. mastrucatus, Gerst., § P, terrestris^'L. §, 

 pratorum, L. ^ , and Proteus, Gerst, a , in these localities 

 make to the flowers of Rh. alpinus, is at least ten times 

 greater than the number of visits by butterflies {Argynnis 



Fig. 61 —The whole corolla, dissected longitudinally. 



Aglaia. L., A. itto, Rott, Lycaena alsus, W. V., L. semi- 

 (irgus, Rott., Larentia albulata, W. V. (?), JBotys spec, Psodos 

 quadrifaria, Sulz.), which, of course, solely search for 

 honey. But the humble-bees treat the flowers in such a for- 

 cible manner, that by their very visits they prove that these 

 flowers are by no means adapted to them. Alighting on 

 the helm-shaped upper lip, the humble-bees are oWiged 

 to turn round in order to reach the face of the flower 



