36o ANGIOSPERMAE—DICOTYLEDONES 



779. Elaeagnus L. 



Flowers entomophilous and hermaphrodite. 



2514. E. angustifolia L. (Herm. Miiller, 'Wait. Beob.,' II, p. 234.) — The 

 flowers of this species are citron-yellow in colour internally, silver-white externally. 



Visitors. — Herm. Miiller, on garden plants, observed the honey-bee, skg., and 

 the hover-fly Syritta pipiens, L., skg. 



XCV. OmyER- LORANTHACEAE DON. 



780. Viscum Tourn. 



Flowers dioecious and entomophilous, with exposed to half-concealed nectar. 



2515. V. album L. (Kolreuter, ' Fortsetzung,' pp. 70-2 ; Loew, Bot. Centralbl., 

 Cassel, xliii, 1890, pp. 129-32.) — Kolreuter declared positively in 1762 that mistletoe 

 is entomophilous, but the plant was considered anemophilous for a long time, until 

 Loew's investigations proved entomophily beyond doubt. In view of the interest to 

 which Kolreuter's description has a claim, I should like to quote from him : — 



' I wish to add a few words regarding an observation which I made last spring 

 on mistletoe. It concerns the quite peculiar construction of those organs which 

 contain pollen, and give it out when ripe, and the only method which Nature employs 

 for the pollination of female plants. 



• A very unsuitable name would be chosen if these organs were called anthers, 

 as in most other plants. They are nothing but a projecting spongy region of 

 a whitish colour, which in the male flower occupies most of the inner surface of the 

 perianth, and is closely fused with it. It is formed of a cellular tissue (parenchyma) 

 through which many hollow passages run in various directions ; these are connected 

 with one another, and are intended to receive the pollen-grains as they are produced 

 by the cells, and finally to let them escape by certain rounded openings into the 

 cavity of the still closed flower. 



' The male flowers do not open all at once, and, as it were, by force, but 

 gradually, scattering the pollen resting within them into the air. The pollen-grains 

 are sulphur-yellow in colour, ovoid in shape, and beset externally with very short 

 slender spines, which are the chief cause of their clinging together. 



' The pollination of female plants, whether growing on the same tree with male 

 stocks or on separate ones at a great distance, is eff'ected entirely by insects, and 

 indeed chiefly by various genera of flies, which eagerly seek the pollen and the sweet 

 fluid secreted by both kinds of flowers and provided as food for them by Nature. 

 The pollen clings to their hairy bodies and is transferred from the male plants to the 

 flowers of female ones. If the nature and quantity of pollen be considered and 

 attention be given to that which happens to these plants during anthesis, it will be 

 easily seen that it would be vain to expect pollination by wind in this case. I there- 

 fore place the mistletoe, without further thought, among those plants pollinated only 

 by insects ; and, so far as I know, it is the first plant in the vegetable kingdom of 

 which it can be said that its fertilization is dependent on insects and its propagation 

 on birds, and that its preservation depends on animals belonging to two quite distinct 

 classes. Doubtless, also, on the other hand, considering their scanty means of 



