THYMELAEA CEAE 



357 



2503. D. Mezereum L. (Herm. Miiller, 'Weit. Beob./ II, p. 236, 'Alpen- 

 blumen/ p. 207; Schulz, 'Beitrage,' II, pp. 159-60; Kerner, 'Nat. Hist. PI.,' Eng. 

 Ed. I, II, p. 3c I ; Kirchner, 'Flora v. Stuttgart,' p. 423 ; Ludwig, ' Adynamandrie 

 V. Erodium macradenum u. s. w.' ; Knuth, ' Bloemenbiol. Bijdragen.' The bright 

 purple flowers of this species are strongly fragrant, thus attracting numerous bees, 

 flies, and Lepidoptera, especially as the crowded blossoms are not hidden by foliage- 

 leaves ; nectar is secreted by the base of the ovary. Hermann Miiller says that the 

 proboscis of an insect probing for this first brushes against the two rows of anthers 

 in the corolla-tube without removing their pollen, and then touches the stigma below 

 them. Pollination will be effected if another flower has been previously visited. 

 When the proboscis, wetted with nectar, is withdrawn, pollen adheres to it and is 

 transferred to flowers visited later. If insect-visits fail, automatic self-pollination 

 takes place by fall of pollen ; this, however, does not seem to be always eff'ective, 

 for all flowers do not set fruits. Kerner says that autogamy seldom occurs on 

 account of the horizontal position of the flowers. 



Schulz observed gynomonoecism and, rarely, gynodioecism ; he also found the 

 flowers at Halle self-fertile. Ludwig, on the contrary, observed adynamandry at 

 Greiz. He transplanted two stocks 

 from different parts of a wood into 

 his garden. They set abundant fruits 

 for eight years, and then one of them 

 died. In spite of frequent insect- 

 visits and artificial transfer of the 

 normal pollen to the fully mature 

 stigmas, no fruits were set by the 

 other plant. Ludwig adds : 



' This case of adynamandry 

 deserves special notice, as A. Schulz 

 found the species to be self-fertile 

 at Halle a. S., where self-poUination 

 was always entirely effective. Adynamandry seems therefore to resemble dichogamy 

 and other oecological adaptations in the various ways in which it can develop on one 

 and the same plant in different places. It might be supposed a priori that adyna- 

 mandry would be evolved in plants of xenocarpous origin in places where the 

 species was abundant and insect-visits numerous after the melting of the snow, while 

 in places where these conditions were reversed it would mean the extinction of the 

 species.' 



Mi^geville (Bull. soc. bot., Paris, xxxv, 1887) describes small fertile and large 

 sterile flowers belonging to this species. 



Visitors. Knuth (Kn.), Herm. Muller (H. M.), and Ludwig (Lud.) almost the 

 same insects, as given below. Considering that the species flowers early, when 

 Lepidoptera, bees, and flies are scarce, it is not surprising that its conspicuous 

 blossoms are visited by nearly all of them. 



A. Diptera. Syrphidae: i. Eristalis tenax Z. (Kn.), skg. ; 2. E. sp. (H. M.), 

 do. B. Hymenoptera. Apidae : 3. Anthophora pilipes jF. S and $ (Kn., H. M.), 

 repeatedly and persistently skg. ; 4. Apis mellifica Z. 5 (Kn., H. M., Lud.), freq., do. ; 



Fig. 358. Daphne Mesereunt, L. (after Herm. Miiller). 

 C. A flower in longitudinal section ; w, nectary. D. Flower 

 from above. 



