76 ANGIOSPERMAE—DICOTYLEDONES 



Visitors which collect or devour pollen touch only the anthers and not the stigma in 

 the short-styled flowers, though this may cause pollen to fall down on the latter, 

 while when they push their heads into the long-styled flowers they touch the stigma 

 and may bring about illegitimate union. 



John Scott and Hermann Muller repeated on this species the crossing experi- 

 ments carried out by Darwin on Primula, and they both came to the same conclusion 

 as he did, i. e. that legitimate unions are most fertile. Muller further found that 

 autogamy and crosses between flowers on the same stock gave still worse results than 

 illegitimate unions, but that, on the contrary, illegitimate union between diff'erent 

 stocks of long-styled flowers resulted in fertility as high as that produced by legitimate 

 unions. 



O. Appel tells me in a letter that he found a number of plants living in com- 

 paratively deep water in swampy ground near Schweinfurt which did not reach to the 

 surface, but nevertheless had set normal fruits. In this case it is clear that pollination 

 took place before the flowers opened, after which the petals expanded. These 

 flowers were smaller and paler than normal ones. 



Visitors. — The following were observed by Herm. Muller. — 



A. Diptera. (a) Empidae: i. Empis chioptera Fall. 5, skg. ; 2. E. livida Z., 

 freq. ; 3. E. pennipes L., freq., skg. ; 4. E. rustica Fall., skg. ; 5. E. vernalis Mg., 

 freq. (h) Aluscidae: 6. Anthomyia sp., skg.; 7. Aricia incana Wiedem., skg.; 8. 

 Siphona geniculata Deg., skg. (c) Syrphidae : 9. Eristalis arbustorum L., not 

 infrequent, skg. and po-dvg. ; 10. E. nemorum Z., do.; 11. Rhingia rostrataZ., freq., 

 skg. B. Hymenoptera. Sphegidae : 1 2. Pompilus viaticus Z., skg. 



The following were recorded by the observers, and for the localities stated. — 



MacLeod (Belgium), the honey-bee, an Eristalis, a butterfly (Pieris sp.), and 

 a beetle. Knuth, the hover-fly Eristalis tenax Z., skg. and effecting legitimate 

 crossing ; (between Plon and Eutin), the butterfly Anlhocharis cardamines Z. $, skg., 

 and 4 hover-flies, skg., and po-dvg. in short-styled flowers — i. Eristalis intricarius Z. ; 

 2. E. tenax Z. ; 3. Rhingia rostrata Z. ; 4. Syrphus sp. 



545. Cortusa L. 



1832. C. Matthioli L. — Kerner describes this species as protogynous. The 

 stigma matures in the bud, and projects from the pendulous flowers before they open. 

 According to Scott this plant is undoubtedly self-sterile, but Treviranus states (Bot. 

 Ztg., Leipzig, xxi, 1863) that other species of the genus are autogamous, the style 

 bending back towards the anthers. 



546. Dionysia. 



According to Kuhn (Bot. Ztg., Leipzig, xxv, 1867), species of this genus are 

 dimorphous. 



547. Gregoria. 



1833. G. vitaliana L. — Kuhn and Kirchner describe this species as hetero- 

 stylous. 



