ROSACEAE 



377 



906. A. acutiloba Stev. — 



Visitors. — Loew observed a Bombyliid (Anthrax morio Z., skg.) and a Syrphid 

 (Eristalis tenax Z., do.) in the Berlin Botanic Garden. 



254. Sanguisorba L. 



Flowers apetalous, associated in capitula ; either with half-concealed nectar, or 

 anemophilous. 



907. S. officinalis L. (Herm. Miiller, 'Fertilisation,' p. 236, 'Alpenblumen,' 

 pp. 224-5.) — In the homogamous flowers of this species the receptacle encloses the 

 ovary, and possesses a nectar-secreting ring that surrounds the base of the style. 

 There are four ovate sepals, concave at their bases, and coloured red above. The)' 

 serve as nectar receptacles, and also as a means of making the flower more con- 

 spicuous. The 50-100 florets of a capitulum open in succession from below 

 upwards in such a way that only a zone one floret deep is in bloom at the same time. 

 In favourable weather insects appear in considerable numbers, and usually effect 



Fig. 118. Alchevtitla Jissa, Schttm. (after Herm. Miiller). A. Hermaphrodite tetramerous 

 flower. AK Pistil of same. B. Female tetramerous flower. B'. Pistil of same. C. Hermaphrodite 

 trimerous flower, with one vestip^ial stamen. C Pistil of same. D. Flower in section. aJk, epicalyx; 

 A, calyx; /{■, 6Iament: j, sepal; .y/, stigma; ov, ovary; «, nectary. 



crossing, for as a rule they touch the stigma and anthers with different sides of their 

 heads. Sometimes, however, they bring about self-pollination, which may easily take 

 place automatically. 



Visitors. — Herm. Miiller observed 4 Muscids, a Syrphid, and 1 1 Lepidoptera in 

 the Alps. Loew noticed one species of hover-fly (Didea alneti Fall.) in the same 

 region, and another (Syritta pipiens Z.) in the Berlin Botanic Garden. Rossler saw 

 a butterfly (Lycaena euphemus Hb.) at Wiesbaden. 



In Dumfriesshire 5 Muscids were recorded (Scott-Elliot, ' Flora of Dumfriesshire,' 

 p. 60). 



Kerner gives the butterfly Lycaena areas Roll., for the caterpillars of which this 

 species is the food-plant. 



908. S. minor Scop. ( = Poterium Sanguisorba Z.). (Herm. Miiller, 'Fertili- 

 sation,' p. 236; Axel), ' Om Anord. for Fanerog. Vaxt. Befrukt., p. 54.) — This 

 species is nectarless, anemophilous, and, according to Kirchner (' Flora v. Stuttgart,' 

 pp. 456-7), coenomonoecious. The male flowers are at the bases of the capitula, 

 the hermaphrodite ones in the middle, and the female ones at the top. Schulz 

 ' Beitrage,' II, pp. 69-70, 188) observed gynomonoecism, andromonoecism, and even 

 pure monoecism. The hermaphrodite flowers are usually homogamous, and the 

 distribution of the sexes varies very much in individual plants. At Ruppin, according 



