LORANTHACEAE 361 



sustenance, these animals in their turn are preserved by the existence of the plant ; 

 a new example by which the exact and necessary interdependence of all things is 

 clearly seen.' 



This masterly description, confirmed about 130 years later by Loew's entirely 

 independent investigations, is a further testimony to the acuteness, as well as to the 

 thoroughness and detail of Kolreuter's observations. Loew describes the flower 

 mechanism somewhat as follows. The tetramerous, leathery perianth is of a yellowish- 

 green colour, and larger in male flowers than in female ones ; the lobes of the former 

 are about 3 mm. long and rather less broad, those of the latter only i mm. in breadth 

 and about the same in length. There are numerous pollen-receptacles on the inner 

 side of the cup-shaped perianth of the male flower. The pollen is not dry and 

 powdery, however, but of a coherent nature, and beset, as Mohl has described it, 

 with fine short spines. The inner hollow of the base of the perianth is covered by 

 a nectary. 



The perianth lobes of the smaller female flowers incline together towards the 

 thick, short, capitate stigma, which in transverse section is bluntly rectangular and 

 about '5 mm. high. In this case the nectary forms a feebly glandular ring, situated 

 between the base of the perianth and that of the capitate stigma, which at this point 

 is contracted to a kind of neck. 



Entomophily is indicated by the flower's striking odour of orange, as well as by 

 the secretion of nectar. In addition to this may be mentioned the nature and com- 

 paratively small amount of pollen, and the fact that the male flowers are larger and 

 perhaps also more strongly fragrant than the female ones. The nectar is situated 

 3-4 mm. deep in the former and is perfectly accessible to an insect probing from 

 above ; Loew says, therefore, that the male flowers belong to class E. In the 

 smaller female flowers the perianth lobes usually so cover the nectary that only the 

 upper surface of the capitate stigma is accessible from outside ; Loew therefore 

 considers the female flowers as belonging to class EC. 



Loew was unable to observe poUinators ; but supposed these to be short-tongued 

 bees. The entrance to the male flower is so narrow (2 mm.), and the inner surface 

 of the perianth so thickly lined with pollen, that a bee with proboscis 3-4 mm. long 

 or even shorter, in probing for nectar, would dust this and its entire head with pollen, 

 which it would inevitably transfer to the stigma of a female flower when probing 

 between the perianth lobes and the capitate stigma. Loew thinks early flying species 

 of Andrena are the pollinators, some of which (A. albicans, A. tibialis, A. praecox, 

 A. parvula, A. fulva, and others) appear as early as the middle of March, the 

 flowering time of mistletoe. As in the case of the willows, which are usually visited 

 by these bees, the mistletoe clumps attract visitors entirely by the fragrance of their 

 nectar, for the usual conspicuousness seems to be unnecessary so early in the year 

 when bright flowers are rare. 



* Kolreuter, as previously described, observed ' chiefly many genera of flies as 

 visitors; these also are able to reach the nectar, which is situated only a few 

 millimetres deep, and thus to effect fertilization in the manner described by Loew. 



Lindman describes mistletoe as monoecious near Stockholm. He compares 

 (Bot. Cenlralbl., Cassel, xliv, 1890, pp. 241-4) the fragrance of the mistletoe-flower 

 with that of apples, or rather of apple-must ; the odour of male flowers is much 



