Dec. 26, 1901. 



AMERICAN BEE JOURNAL 



821 



now that attention has once been 

 drawn to it, it can be recogfnized as a 

 general principle running through all 

 branches of the vegetable and animal 

 kingdoms. Although, as was pointed 

 out by Darwin, some plants can be and 

 are fertilized by their own pollen, it is 

 always of greater benefit to their de- 

 scendants for flowers to be fertilized 

 by pollen from other flowers of the 

 same kind growing upon other plants. 

 He summed up his observations with 

 the trite observation, "Nature abhors 

 perpetual self-fertilization," which was 

 first enunciated in his great work pub- 

 lished in 1862 on the fertilization of 

 orchids. The publication of this classic 

 work marks the beginning of one of 

 the most important eras in the history 

 of the science of botany. Since then 

 endless observations have confirmed 

 the accuracy of Darwin's law, and it 

 has been found that in the vast major- 

 ity of plants special appliances exist 

 which will secure a more or less fre- 

 quent inter-cross, and that in many 

 these appliances completely exclude 

 the possibility of self-fertilization. 



The cross-fertilization of some plants 

 is insured by the male and female 

 organs occurring in separate flowers, 

 either on the same or different plants. 

 Familiar instances of male and female 

 flowers on the same plant are the male 

 catkins of such trees as the butternut, 

 hickory, the birches, oaks and hazels. 

 The female flowers are much less con- 

 spicuous but easily recognizable near 

 the tip of the twigs. In the vrillows 

 we find the male and the female cat- 

 kins on separate trees, each tree bear- 

 ing either staminate male flowers, or 

 pistillate female ones. In many cases 

 where the two sexes occur in the same 

 flower, self-fertilizing is prevented by 

 the male and female organs coming to 

 maturity at different times, sufliciently 

 far apart for it to be impossible for the 

 pistil to be fertilized by the pollen borne 

 on the same flower. In many cases there 

 are remarkable contrivances which pre- 

 vent the impregnation of flowers by 

 their own pollen. In the species of 

 primrose — and no better example can 

 be found than the well known house- 

 plant from the Himalayas— /';-?';««/a 

 obcotiica—W. will be found that the flow- 

 ers on different plants are dimorphic, 

 some flowers having the tip of the pis- 

 til at the mouth of the tube and the 

 anthers well down towards the bottom, 

 while in other flowers this order is re- 

 versed, and the anthers are produced 

 at the mouth of the tube and the pistil 

 is so short that it does not reach half 

 way up. Darwin proved by growing 

 many plants from the seeds that by 

 far better plants were obtained by the 

 flower bearing long or short pistils be- 

 ing crossed with pollen from the other 

 kind of flower. There are some flowers 

 which are actually sterile to their own 

 pollen, but can be fecundated readilv 

 with pollen from flowers growing on 

 another plant of the same species. It 

 has been pointed out by Prof. Waugh, 

 of Vermont, that this is the case with 

 the red American plums, and it is also 

 the case with many varieties of apples 

 and pears. This fact at once indicates 

 the important bearing the presence of 

 insects in an orchard at the time of 

 blossoming has upon the production of 

 an abundant fruit crop. Moreover, it 

 can be shown that, owing to its size, 

 weight and habits, no insect is so well 

 calculated to insure the fertilization of 



fruit-blossoms as the honey-bee, which 

 plies rapidly from plant to plant, and 

 by running over the flowers in search 

 of pollen or nectar, brushes off the pol- 

 len and carries this vitalizing element 

 on the hairs of its body to the next 

 flower visited. The habit of the bees, 

 which has frequently been noticed, of 

 confining the visits when collecting 

 largely to the same kind of plant, is 

 taken advantage of by the bee-keeper 

 to store up at certain seasons particu- 

 lar kinds of honey, such as apple, 

 raspberry, basswood, clover and buck- 

 wheat honeys. This habit is also 

 manifestly advantageous to the plants 

 on account of the pollen which is car- 

 ried by the bee being of the kind neces- 

 sary for the fertilization of its flowers, 

 which could not be effected if the pollen 

 were that of some other kind of plant. 



A few weeks ago I saw a striking in- 

 stance confirmatory of this well-known 

 fact. High upon the summit of Mount 

 Che-am in the coast range of British 

 Columbia, are magnificent mountain 

 meadows, undulating plateaux, thickly 

 covered during the month of August 

 with the greatest profusion of brilliant 

 flowers — wide stretches of golden arni- 

 cas, crimsom, green and white moun- 

 tain heathers, beds of veratrus, valer- 

 ian, lupines, large, white umbillifers, 

 crimson cartilleias, yellow adder's ton- 

 gue, lilies, potentillas and waving 

 grasses and sedges. This gigantic 

 flower-bed, as might be expected, sim- 

 ply teemed with insect life. Butterflies 

 sailed lightly from place to place ; flies, 

 beetles and small bees hurried and 

 scurried in every direction, making the 

 most of the short mountain summer, 

 and the whole producing a picture of 

 the greatest delight to the naturalist 

 whose only, ever-present regret was 

 that so few others could enjoy the en- 

 chanting scene. 



Co.nspicuous on the purple spikes of 

 the lupines were numerous, busy, 

 grumbling, clumsy bumble-bees, crawl- 

 ing over the gay flowers, rifling them 

 of their nectar, and filling theirpollen- 

 baskets with bright red pollen, which 

 was most conspicious on their black 

 and white bodies, and strikingly differ- 

 ent in color from the ordinary pollen 

 collected elsewhere. 



There are endless devices in flowers 

 to secure the distribution of pollen at 

 the time it will be of most use, and also 

 for its protection from moisture after 

 it had been emitted from the anthers. 

 This is secured, in most instances, by 

 the shape of the flowers, or the position 

 of the floral leaves; again, the male 

 and female organs of some flowers are 

 very sensitive, the pollen being cast 

 forth with some violence as soon as the 

 stamens are touched by insects. 



An instance of this is to be found in 

 the common Canadian swamp-plant, 

 called Lambkin or Swamp Laurel ; the 

 anthers are held down in small depres- 

 sions round the edge of the corolla, 

 and when an insect visits the flower, 

 the stamens spring up, the anthers 

 burst, and the pollen is thrown against 

 the insect's body. The same thing may 

 be observed in the common barberry 

 flower. 



In addition to the classes of plants 

 already referred to. which are sterile 

 to their own pollen (and in a few re- 

 markable instances where the pollen is 

 actually poisonous to the pistil of the 

 same flower) th<;re are numberless 

 species which are partially sterile when 



fertilized with their own pollen, and to 

 a less degree when fertilized with pol- 

 len from close relatives, such as seed- 

 lings from the same parent as the plant 

 bearing the flowers ; and finally, in a 

 large class where there is no apparent 

 obstacle to self-fertilization, cross-fer- 

 tilization often ' occurs from what is 

 known as the prepotency of pollen 

 from another individual over a plant's 

 own pollen. 



The agency by which pollen is trans- 

 ported from one flower to another is 

 either animate or inanimate, and cer- 

 tain peculiarities will be found in flow- 

 ers characteristic of each class. The 

 inanimate agency with most flowers is 

 the wind, and in these flowers the pol- 

 len is dusty and exceedingly light, so 

 as to be carried on the lightest breeze ; 

 the flowers are inconspicuous and there 

 is no nectar nor perfume. On the other 

 hand, in those flowers which are depen- 

 dent on an animate agency, which is 

 mainly insects of various kinds, these 

 insects must be attracted to the flowers; 

 and we accordingly find that brilliant 

 colors and far-reaching odors are devel- 

 oped. 



These alone, however, would be of 

 small gratification to the visitors ; 

 consequently, something more satisfy- 

 ing is provided, namely, nectar and 

 pollen, which form the food of vast 

 hordes of the insect world, and particu- 

 larly of the honey-bee. Moreover, the 

 remarkable provision is made that 

 these attractions only appear just at 

 the time when the visits of insects can 

 be of a definite benefit to the plant ; 

 and further than this, an endless vari- 

 ety in the structure of the leaves, stem 

 and flowers of plants makes easy the 

 access of such species as will be of use, 

 but retards or keeps out entirelj' those 

 which would only regale themselves on 

 the sweets provided without conferring 

 any benefit in return. A pollen-grain 

 is somewhat analogous to a seed ; as 

 soon as it reaches the stigma, the vis- 

 cid portion of the pistil, a sort of 

 growth begins, and delicate tubes are 

 pushed out and run down through the 

 tissues to the ovary. Through these 

 tubes the vitalizing principle (the 

 fovilla) reaches and fecundates the 

 ovules in the ovary. The period dur- 

 ing which the pollen and the stigma 

 are in a fit condition for fertilization is 

 only of short duration. Those insects, 

 therefore, which can fly quickly from 

 plant to plant are much better adapted 

 for this %vork than the slower moving, 

 wingless, creeping insects which would 

 be much more likely to have the pollen 

 brushed from their bodies in their 

 journey from plant to plant or even 

 from flower to flower. 



The size even of flying insects is also 

 a matter of importance so that their 

 bodies may come in contact with the 

 anthers of one flower and the pistil of 

 another, and most marvellous contri- 

 vances will be discovered when looked 

 for in the blossoms of flowers, the ef- 

 fect of which is to exclude those visit- 

 ors which are not profitable. Such are 

 modifications in the shape and size of 

 the corolla, the presence of tufts of 

 hair, barbed spikes and bristles around 

 the nectary, the secretion of the nectar 

 at the bottom of long spurs or deep 

 tubes of the corolla, etc. Wingless in- 

 sects are kept from getting to the nec- 

 tar by even more numerous construc- 

 tions : reflexed bristles, copious hairs, 

 viscid glands or viscid rings on the 



