GENTIANEAE 109 



heterostyly in England and associated dimorphism of the pollen-grains, but I was 

 not able to confirm this in the North Frisian Islands, nor could Schulz and 

 Kirchner do so in Central and South Germany. The two latter investigators, 

 however, found the style to vary in length in different stocks, and even, in rare 

 cases, on the same one. In long-styled forms the stigma may be at the level 

 of the anthers, though usually lower; in short-styled ones it is situated in the 

 opening of the corolla -tube. Schulz observed feeble protandry as well as 

 homogamy, and Townsend records protogyny for the variety E. capitata Willd. 



The flowers close periodically, and Kerner states that anthesis lasts for five 

 days. Schulz and Kirchner call attention to variations in their size. Hermann 

 Miiller is of opinion that the spiral twisting of the anthers (resembling the screw- 

 Jike torsion of the styles in Dianthus Carthusianorum and its allies) is probably 

 an adaptation to the slender proboscis of butterflies, and that despite the absence 

 of nectar these insects bore for sap in the bases of the flowers with the sharp 

 processes on the tip of that organ. Wamstorf states that the flowers open between 

 6 and 7 a.m., closing again between 12 noon and i p.m. He describes the 

 pollen-grains as yellow in colour, ellipsoidal, opaque, densely tuberculate, up to 

 44 IX long and 23 /it broad. 



Visitors. Herm. Miiller gives the following list for Thuringia (T.) and 

 Westphalia. 



A. Diptera. Empidae: i. Empis livida Z., skg. B. Hymenoptera. Apidac. 

 2. Andrena aestiva Sm. $, po-cltg. ; 3. A. gwynana K. 5, do.; 4. Halictus morio 

 F. $, do. C. Lepidoptera. All boring the tissue at the base of the flowers. 

 (a) Noctuidae : 5. Agrotis pronuba Z., in large numbers, persistently skg. ; 6. Plusia 

 gamma Z., do. (b) Rhopalocera : all skg. : 7. Hesperia lineola 0. ; 8. Lycaena 

 damon S.-V.; 9. Melitaea athalia E!sp.; 10. Pieris rapae Z. {c) Sphingidae: 

 II. Macroglossa stellatarum Z., skg. (T.); 12. Zygaena carniolica Scop.^ do. 



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



Knuth, the po-dvg. hover-fly Syrphus balteatus Deg. MacLeod (Flanders), 

 the hover-fly Eristalis arbustorum Z. (Bot. Jaarb. Dodonaea, Ghent, v, 1893, p. 383). 

 Handlirsch, the fossorial wasp Gorytes tumidus Pz. Scott-Elliot (Dumfriesshire), an 

 Empid, a hover-fly, and 2 Muscids ('Flora of Dumfriesshire,' p. 118). 



1920. E. linariifolia Pers. (Knuth, ' Bl. u. Insekt. a. d. nordfr. Ins.,' p. 106.) 

 The flower mechanism of this species agrees with that of E. Centaurium, but the 

 style does not bend away from the stamens to the same degree. 



1921. E. ramosissima Pers. ( = E. pulchella Hornem.). (Knuth, loc. cit. ; 

 Schulz, 'Beitrage;' Kerner, 'Nat. Hist. PI.,' Eng. Ed. i, II, p. 366.) The flower 

 mechanism agrees with that of E. linariifolia, and here again the divergence of the 

 stigma from the anthers is not so marked as in E. Centaurium, but the stamens 

 and style are almost always erect, so that, should insect-visits take place, cross- 

 and self-pollination are equally possible, while the latter may also take place 

 automatically. Schulz states that the short-styled form is particularly common 

 in Central Germany. Kerner says that autogamy is effected by elongation of 

 the corolla in the course of anthesis, the anthers being raised in this way to the 

 level of the stigma. He adds that anthesis lasts for six days, and that the flowers 

 open about lo-ii a.m., closing again 3-4 p.m. 



