i84 



ANGIOSPERMAE—DICOTYLEDONES 



xxxviii, 1896; Schulz, 'Beitrage,' II, pp. 46—7; Kirchner, 'Flora v. Stuttgart,' 

 P- 235.) — Hermann Miiller describes the flowers as protogynous, with stigmas 

 persisting for a long time, while A. Schulz found them to be almost always 

 homogamous, though sometimes slightly protandrous or slightly protogynous. At 

 the base of each of the five outer stamens there is a fleshy swelling, which secretes 

 a relatively large drop of nectar. The anthers of the five outer stamens dehisce 

 first. Insect visitors regularly effect cross-pollination, for they touch the stigmas 

 before the anthers. Failing insect-visits, automatic self-pollination takes place, 

 the stamens gradually curving inwards till they touch the stigmas. Sometimes 

 the anthers of the five outer stamens are vestigial. 



Warnstorf states that the flowers are homogamous and autogamous at Ruppin. 

 The long stigmatic branches — usually three, more rarely two — curve outwards, often 

 becoming hook-shaped, and arch over the stamens in such a way that self-pollination 

 necessarily results. Self-pollination also takes place by apposition of the stamens 

 to the stigmas. The styles are rarely vestigial. The parts of the flower are 

 frequently in fours. 



Visitors. — The inconspicuous odourless flowers, with petals shorter than the 

 sepals, are but rarely visited by insects. 



Hermann MuUer observed the following. — 



A. Coleoptera. {a)Niti- 

 dulidae: i. Meligethes, nect- 

 1kg. (b) Phalacridae : 2.01ibrus 

 affinis Sturm., nect-lkg. 



B. Diptera. [a) Bibio- 

 nidae : 3. Dilophus vulgaris 

 Mg., nect-lkg. (3) Mtacidae : 

 4. Sapromyza rosida Fa/I., 

 nect-lkg. 



MacLeod observed an 

 Empid in Flanders (Bot. 

 Jaarb. Dodonaea, Ghent, vi, 

 1894, p. 162). 



In Dumfriesshire an Em- 

 pid, several other Dipters, and 

 a wasp, have been recorded 

 (Scott-Elliot, ' Flora of Dum- 

 friesshire,' p. 26). 



460. M. muscosa L. (Herm. Muller, ' Alpenblumen,' pp. 187-8; Schulz, 

 ' Beitrage,' II, pp. 45-6.) — This species bears protandrous hover-fly flowers. There 

 are eight stamens, of which the four outer ones first raise themselves and open their 

 anthers, then the four inner stamens do the same, and when all eight have withered 

 the styles and stigmas develop. Self-polHnation is, therefore, only occasionally 

 possible (see Fig. J4). Schulz says that besides hermaphrodite flowers there are 

 also female ones on gynodioecious, more rarely on gynomonoecious plants. 



Visitors. — Herm. Muller frequently observed small hover-flies — especially Sphe- 

 gina clunipes Fall. — which hover in front of a flower, alight to lick nectar or devour 

 pollen, and then go off to another. A. Schulz noticed small bees as well as flies. 



Fig. 54. Moehringia muscosa, L. (after Herm. Miiller). A. 

 Flower in the first (male) stage. B. Stamens of the same flower, 

 seen from without. C. Flower in the second (female) stage, after 

 removal of calyx and corolla. 



