188 



CASSELL'S POPUIAE GABDENrNG. 



complicated structure, the mechanical arrangements, 

 and powerful fragi-ance of flowers. These are all 

 inducements held out to insect visitors, contrivances 

 which compel the unconscious insect to enter the 

 flower in this way, follow this particular course 

 and no other, leave the bloom in this prescribed 

 manner, and so bring about the transfer of pollen 

 from one flower to the stigma of another. No 

 doubt the insect is profoundly unconscious of the 

 work he has really to do in the world. His object 

 in visiting the flower is the selfish one of providing 

 for his own necessities, or the requirements of his 

 ofispring, or of the community of which he is a 

 member, as in the case of bees and ants. There are 

 hundreds upon hundreds of different variations 



not directly concerned in the process of fertilisa- 

 tion, are thus indirectly of very great impoiianoe 

 to it, and moreover they serve, in the first in- 

 stance, to protect and enclose the more impor- 

 tant parts. In this place we cannot do more 

 than advert to some of the peculiarities of these 

 " floral envelopes." In the Willow, as we have seen, 

 they are wanting, or represented by a single scale ; 

 in the Poplar by a single cup ; in the Alder (Fig. 81) 

 by a " perianth " of four separate green lobes ; in 

 the lily (Fig. 66) by six coloured ones of regular 

 form; in the Foxglove (Fig. 75) by an outer 

 green calyx of five sepals, and an inner sleeve-like 

 " corolla," consisting in this instance of five " petals " 

 of unequal size, growing together for nearly their 



Fig. 81.— Infloeescknce op the Alder. 



in the mechanism of flowera correlative with the 

 hundreds upon hundreds of variations in the con- 

 formation, and mode of life, of insects. This 

 flower, let us say by way of illustration a Eho- 

 dodendron, has upturned anthers which open at 

 the tips, and spots on the upper part of the coroUa 

 and nowhere else. It has colour, fragrance, and 

 nectar for the insect, which in its search for the latter 

 is guided by the spots aforesaid, and so necessarily 

 takes its course over the anther-pores, brushing out 

 the pollen from them as he goes, and having rifled 

 the flower of its honeyed treasure, and its pollen, 

 flies off to another flower, where, if the upturned 

 stigma over which, with gentle compulsion, he is 

 forced to go, is just in 'condition to receive the pol- 

 len, fertilisation occurs; or if otherwise, no result 

 follows. Another flower, dull in colour and un- 

 attractive, scentless by day, diffuses by night a rare 

 fragrance to attract the night-flying insects ; and so 

 on, and so on, till actual verified truth becomes 

 more wonderful than fictitious romance. 



Tlie Coverings of the Flower.— The so- 

 called non-essential parts of the flower,' although 



whole length, and only veiy slightly separated at 

 their lips. The irregular ;£orm, and the disposition 

 of the coloured spots, the pendulous position of the 

 flower, the arrangement of the stamens, all indicate 

 the necessity fpr insect visitation, and consequent 

 cross-fertilisation. 



Dimorphic Flowers. — In connection with this 

 subject it is requisite to mention certain cases in 

 which two or more kinds of flower exist on the 

 same plant ; thus, in the common Violet there is the 

 pui-ple-coloured fragrant flower with which we are 

 all famUiar, and which, from its highly irregular 

 form and powerful fragrance, is specially adapted 

 for cross-fertilisation by insect agency ; and there is 

 another form of Violet flower very common, though 

 often overlooked. In this second form of flower the 

 petals are green, unattractive, and devoid of fragrance, 

 they are near the ground, and little, if at all, up- 

 raised from its surface. They present little or no 

 attractions for insects, and the petals either do not 

 unfold at all, or only to a vei-y slight degree. Such 

 flowers are found to be verj' fertile, and produce 

 abundance of seed, which must in this case be 



