THE PLANT AND ITS HELPERS 



957 



array of hairs. Indeed, it is not until 

 the stigmas have withered, and the anthers 

 have come to perfection, dusting tiie 

 flies with pohen, that the fringe of bristles 

 dries up and allows the flies to go about 

 their business once more. 



It is known that humming birds play 

 a considerable part in the fertilisation of 

 many tropical American plants. By their 

 peculiar habit of flight, 

 these little birds are well 

 adapted for hovering over 

 blossoms and sipping the 

 nectar from the blooms 

 with their long beaks. A 

 great variety of flowers 

 appear to be visited by 

 these tiny creatures, al- 

 though they seem especi- 

 ally to favour the blossoms 

 of the Fuchsia and Lapa- 

 geria, as weU as some of 

 the Passion Flowers. In 

 Britain a large number of 

 our trees are cross-fertil- 

 ised by the agency of the 

 wind, and in no cases are 

 the blossoms large or gaily 

 coloured. Most people 

 must be familiar with the 

 long hanging catkins of 

 the Hazel, which as they 

 reach their maturity are 

 among the first signs of 

 approaching spring. These 

 are, of course, only the 

 male organs of the plant, 

 and it requires some 

 searching to find the 

 clusters of crimson threads 

 which represent the stig- 

 mas. On a day when the anthers have 

 come to perfection the smallest puff of air 

 blows the pollen in little clouds through 

 the leafless branches, and a certain 

 amount of it is sure to find a resting place 

 on the female organs and in this way to 

 bring about pollination. 



The Scots Pine presents a most striking 

 example of a tree which relies upon wind 

 fertilisation. In the month of June, when 

 the anthers arrive at maturity, we may 

 see the pollen hanging over the branches 

 in dense clouds. The dispersal of the 

 grain from tlie male flowers to the unde- 

 veloped female cones is facilitated by the 



THE NECTARIES OF THE 

 CUCKOO FLONXfERS ARE AT 

 THE BASE OF THE TWO 

 SHORT STAMENS, WHILST 

 THOSE OF THE BUTTER- 

 CUP ARE AT THE BOTTOM 

 OF THE PETALS. 



fact that the pollen is provided with 

 minute wings. At the time when the 

 pollen floats away on the breezes the 

 ovules on the female cones e.xude a sticky 

 substance, which ensures the retention 

 of any grains which happen to come in 

 contact with it. 



A certain number of plants rely upon 

 water as a medium for the distril)uUon 

 of their pollen. Of this a 

 British marine species, the 

 Grass Wrack, is an ex- 

 ample. The pollen grains 

 are here of tubular form, 

 and being of like specific 

 gravity to the water, are 

 conveyed by the currents 

 from the antliers of the 

 male flowers to the stig- 

 mas of the female organs. 

 More strange still is the 

 story of the Italian Eel 

 Grass [Vallisneria spiralis), 

 a native of Southern 

 Europe. The male and 

 female flowers are pro- 

 duced on different speci- 

 mens, and at first both 

 kinds are developed low 

 down, quite close to the 

 roots of the plant. 



As soon as the female 

 b lo s s o m s have nearly 

 matured, however, the long 

 stems on which they are 

 borne (previously packed 

 away in a receptacle) un- 

 wind and bring the flower 

 heads to the surface. At 

 this time the submerged 

 male buds become de- 

 tached and rise to the surface. After a 

 short interval the blossoms open back 

 three sepals, and in this way form a kind 

 of raft upon which they can float about, 

 driven in ah directions by the wind. 

 Sooner or later the majority of the little 

 boats will be certain to come to a halt 

 against one of the female blossoms, with 

 the result that the projecting stamens can 

 discharge the pollen grains upon the wait- 

 ing stigma. After fertilisation the long 

 stalk of the female blossom coils up spir- 

 ally, and gradually carries the ovules down 

 to the mud bottom, where the seeds may 

 ripen in safety. S. Leo.n'ard Bastin. 



