208 



ANGIOSPERMAEDICOTYLEDONES 



Herm. Miiller calls attention (' Fertilisation,' p. 14) to a peculiarity of the flowers 

 of this species, i. e. that they afe not adequately protected against nectar-thieves. 

 In the afternoon, when the flowers begin to close, the honey-bee frequently thrusts 

 its proboscis between the five sepals of blossoms which are still fresh though shut, 

 and thus empties the nectar receptacle from outside. On some few occasions Miiller 

 even observed bees which had rifled several such flowers in this way, continuing 

 their depredations on neighbouring ones that were still open. 



517. M. rotundifolia L. ( = M. borealis Wallm). (Herm. Miiller, ' Fertilisation/ 

 pp. 142-4, 'Weit. Beob.,' II, p. 221; Warnstorf, Verh. bot. Ver., Berlin, xxxvii, 

 1895.) The flower mechanism of this species at the beginning of anthesis is the 

 same as that of the last one. But, in correlation with its much smaller and less 

 brightly coloured flowers, M. rotundifolia is capable of automatic self-pollination, 

 which is necessary for the maintenance of the species since the number of visitors 

 is naturally much smaller. The stamens remain so far erect that the pollen-covered 

 anthers are touched by the recurved stigmatic branches (see Fig. 60). 



Fig. 6a. Malva sylveslris, Z.., and M. rotundifolia, L. (after Herm. Mailer). M. sylvestris; 

 (1) Column of stamens in the bud, enclosing; the styles. (2) Sexual organs in the first (male) stage. 

 (3) The same in the transition from the first to the second stage. (4) The same in the second (female) 

 stage. (5) M. rotundifolia in the last stage, showing self-pollination. . a, anthers ; si, stigmas. 



Warnstorf gives a somewhat different account, as follows. Most of the German 

 species of Malva, such as M. Alcea, M. sylvestris, and M. neglecta, possess strongly 

 protandrous flowers, so that self-pollination appears to be excluded, at least in the 

 first stage, though later on it is possible, since some of the large thickly spinulose 

 pollen-grains remain adhering to the dehisced anthers. But M. rotundifolia, on 

 the other hand, has very small inconspicuous flowers, usually concealed under a 

 dense covering of the leaves. They can scarcely depend upon insect-visits, and 

 are almost homogamous. (See, however, the appended list of visitors.) Even at 

 the beginning of anthesis, the stigmas have more or less curved outward to receive 

 pollen, and are at once seen on looking down into the open flower. Owing to 

 the smallness of the hidden flowers, insect-visits are rendered impossible, or at least 

 very unlikely, but homogamy completely compensates for this. In Buslar (Pome- 

 rania), where this species as well as M. neglecta is quite common, Warnstorf 

 only on a few occasions observed in the flowers a few winged ants, upon the wings 

 of which were numerous pollen-grains, so that they were clearly able to effect 

 cross-pollination. 



