35 ANGIOSPERMAEDICOTYLEDONES 



of this species on the dunes, especially those of the island of Rom, but have had 

 little opportunity of observing visitors there. The diameter of the white corolla is 

 about 3 cm. Anthers and stigmas mature simultaneously when the flowers open. 

 Although the stamens curve away from the stigmas, so that insects- visits render 

 cross-pollination possible, yet automatic self-pollination takes place in the absence of 

 these insects, for when, owing to the frequent violent winds on the islands, the little 

 plant strikes against the ground pollen can easily be transferred to the adjacent 

 stigmas. 



Visitors. I saw several po-dvg. Muscids in the island of Rom, as well as 

 Forficula and a few po-dvg. beetles. 



Verhoeff (Norderney) observed a beetle (Phyllopertha hordeola Z., freq., po-dvg.) 

 and a humble-bee (Bombus terrester Z., a , po-cltg.). 



832. R. rubiginosa L. (Herm. Miiller, 'Weit. Beob.,' II, pp. 239-40; 

 Knuth, ' Bl. u. Insekt. a. d. nordfr. Ins.,' pp. 70, 154.) In this species not only the 

 flowers but also the foliage-leaves are fragrant, so that the latter help to attract insects. 

 The bright pink flowers afford them not only pollen, as in the other species of the 

 genus, but also nectar, as shown by Hermann Miiller. It is secreted in quite a thin 

 layer on the broad fleshy margin of the receptacle. The flowers of this species are 

 slightly protogynous, so that cross-pollination necessarily takes place when insects 

 visit them at the beginning of anthesis. At this stage numerous fully mature stigmas 

 are crowded together in the middle of the flower, as projecting pillow-like swellings, 

 affording to insects a convenient alighting-place and platform. The stamens at this 

 time are still curved outwards, and their anthers as yet unripe. Later on, when the 

 anthers dehisce, the filaments bend together above the middle of the flower, so that 

 automatic self-pollination takes place. Kerner states that the flowers are open from 

 5 a.m. till 9 p.m. 



Visitors. In the island of Amrum I only observed the honey-bee, po-cltg. 



Herm. Miiller gives the following list. 



A. Coleoptera. (a) Chrysomelidae : Crytocephalus sericeus Z., devouring the 

 flowers; 2. Luperus flavipes Z., freq. (b) Ttlephoridae : 3. Danacea pallipes Pz., in 

 very large numbers wiihin the flowers. B. Diptera. Straiiomyidae: 4. Oxycera 

 pulchella Mg., occasional. C. Hymenoptera. Apidae : 5. Bombus pratorum L. 

 j, po-cltg. ; 6. B. terrester Z. 5, do. 



833. R. alpina L. 



Visitors. Herm. Miiller (' Alpenblumen,' p. 215) saw a small bee (Halictus). 



834. R. centifolia L. (Herm. Miiller, 'Fertilisation,' pp. 237-8, 'Weit. 

 Beob.,' II, p. 239; Knuth, ' Bloemenbiol. Bijdragen.') 



Visitors. I (Kn.) noticed that this and other cultivated double species received 

 a moderately large number of visits ; Herm. Miiller (H. M.) records more numerous 

 visitors for R. centifolia alone. 



A. Coleoptera. (a) Cerambycidae: 1. Clytus arietis Z., destroying the delicate 

 parts of the flowers, especially the anthers (H.M.) ; 2. Grammoptera ruficomis F., 

 very numerous, do. (H. M.) ; 3. Strangalia atra Latch., as 1 (H. M.) ; 4. S. attenuata 

 Z., do. (H.M.). {b) Cistelidae: 5. Cistela murina Z., as 1 (H.M.). (r) Dervustidar. 

 6. Anthrenus fuscus Lit., rare (H. M.) ; 7. A. pimpinellae F. (H. M.) ; 8. A. scrophu- 



