June, 1907 



AMERICAN HOMES AND GARDENS 



from the stamens upon the soft, velvety scales of the head, 

 or upon the tongue itself (Fig. 5). 



It becomes obvious from what we have already seen that 

 by an increase in the length of its tube a flower might greatly 

 restrict the number of insects capable of reaching its nectar. 

 By this means, a few moths — presumably most fitted to carry 

 on the cross-fertilization of the particular plant in question — 

 might be given the exclusive right of visiting such a bloom. 

 As a matter of fact, this state of things is actually existing. 

 Species of hawk moth not a few have tubular tongues, or 

 trunks, twice and even thrice as long as their own bodies, 

 and such moths visit flowers whose nectar is stored at the 

 extremity of abnormally long tubes. A flower of this kind 

 is that of the Nicotiana, or tobacco-plant, certain varieties of 

 which are frequently grown in gardens (Fig. 6). This blos- 

 som, too, affords an interesting example of those plants 

 which reserve themselves exclusively for crepuscular or night- 

 flying moths. Such flowers are usually either white or yel- 

 low — the reason for this being obvious in that bright colors 

 lose their conspicuousness at the approach of twilight, and 

 therefore fail to be of use in ad\ ertising the whereabouts of 



It will be noticed that the dark veins with which the paler 

 ground-color is traced all converge about the mouth of 

 the spur. These lines are known as "honey guides." Their 

 purpose is to assist the moth in discovering quickly the 

 narrow entrance of the spur into which its long tongue must 

 be inserted. 



Of all flowers, those which exhibit the most wonderful and 

 varied contrivances for securing cross-fertilization are the 

 orchids. Space will not allow us to dwell long upon this 

 fascinating subject, but one or two points must receive brief 

 notice. We may select as a special instance the common 

 spotted orchid (Fig. 8) of English meadows, as it is typical 

 of other orchids in different parts of the world. The blos- 

 som possesses a spur, and in this the nectar is stored. Sta- 

 mens, as such, are non-existent; but their place is taken by 

 two "pollen masses." These pollen masses are stored in 

 two little bags or pockets. Their stalks are sticky, and are 

 so placed that they come into contact with the bee's head as 

 he is inserting his tongue into the spur in search of honey. 

 In fact, they become gummed to the insect's head; and when 

 it leaves the flower, the pollen masses are dragged from 



IO~Wild Arum 



12 — Humble Bee Visiting 

 Pea Blooms 



1 I — Humming Bird Visiting Fuchsia 



the flower. At noon the tobacco flowers are all tightly shut 

 up and look quite withered; but at the approach of dusk 

 each one holds up its head, expands, and becomes a bright 

 star, readily distinguished at a distance long after the reds 

 and blues and purples of other flowers have faded away in 

 the gloom. 



Another common flower well worthy of special obser- 

 vation is the common nasturtium (Fig. 7), better known, 

 perhaps, as the Indian nasturtium. The blossom is won- 

 derfully adapted for the visits of a flying insect possess- 

 ing a long tongue. In the first place, we see that the calyx 

 is modified to form a long spur; and at the extremity of this 

 the nectar is stored. This secures the flower from invasion 

 by all short-tongued flying insects; but in order that minute 

 creeping intruders, such as ants, may be kept at a distance, 

 the flower has a kind of hedge or fence running right across 

 the three lower petals. Ants find it impossible to cross this 

 barrier, nor is it any easier for them to gain the interior of 

 the flower by means of an attack from the rear. 



The two upper petals of the Tropaeolum are to be re- 

 garded as its banners of welcome and advertisement to its 

 moth visitors. They supply a good instance, too, of a par- 

 ticular kind of marking very common among certain flowers. 



their pockets and carried away. At this stage they stand 

 erect on the bee's head. But as the insect passes rapidly 

 through the air, the pollen masses dry, and their stalks bend 

 over, so that when the bee visits the next orchid-bloom they 

 are pointing directly toward the gummy surface of the 

 stigma (or pistil) which has its place just below the pollen 

 masses. With this they come into contact, adhere, and thus 

 pollination takes place. 



Many flowers treat their insect visitors very badly. There 

 are certain kinds of Arum which deliberately entrap small 

 flies which come to them. The structure of these blossoms 

 is peculiar. There is a large pale leaf, known as the spathe, 

 with a curious liver-colored club within. Those parts do not 

 really represent the flower at all; their purpose is to attract 

 inquisitive flies. Down below, on the stalk of the liver- 

 colored club, the real flowers are arranged. Lowest are the 

 females, like a number of little knobs; next are the males; 

 and above these, at the entrance to the bulb portion of the 

 spathe, are a number of abortive flowers which look like so 

 many hairs (Figs. 9 and 10). 



When flies visit a newly opened arum-bloom, they force 

 their way past these hair-like flowers, and find themselves in 

 a roomy chamber. Probably some of them have come from 



