MYSTERIES AND REVELATIONS OF THE PLANT WORLD 



1277 



them. I kept a dozen of them in water for a year and 

 found by frequent weighing that they did not absorb 

 even a grain of water; but I also found that if they are 

 planted in fall they will sprout in the first or second 

 spring following. One seed I gave to a tame gray 

 squirrel. He drilled a small hole through the shell, but 

 dropped the seed as soon as he had reached the meat. 



The tree, although one of our rarer forest trees, is 

 fairly well distributed from Tennessee to Ontario and 

 from Pennsylvania to the Indian Territory, but it grows 

 in small colonies, often miles apart. It is found on rich 

 bottom lands and on islands in large lakes. It may be 

 that grouse occasionally swallow the seeds as they swal- 

 low pebbles, for it seems impossible that the seeds could 

 reach islands without the 

 aid of some bird. It is 

 likely that the passenger 

 pigeons in days gone by 

 distributed the seeds of the 

 coffee tree. 



A small cactus, the joint- 

 ed opuntia, is widely dis- 

 tributed in arid regions 

 from New Mexico north- 

 ward. In some mysterious 

 way it has reached many 

 dry rocky ledges in humid 

 Minnesota and Wisconsin. 

 A few years ago on a canoe 

 trip on Lake of the Woods 

 I found a fresh joint of 

 this cactus among the 

 boulders of the Ontario 

 shore in a densely wooded re- 

 gion. How the plant reach- 

 ed this spot has remained 

 a secret to me. 



A whole book of miracles 

 might be written on the 

 mutual adaptations between 

 flowers and insects. That 

 many flowers are adapted 

 to cross-pollination by in- 

 sects is a fact of common 

 knowledge, but that some 

 of these adaptations have 

 been perfected, one might say, beyond perfection, is not 

 so generally known. 



All our species of milkweed';, for instance, depend for 

 pollination absolutely on insects. The peculiar structure 

 of the flowers makes any other method impossible. More- 

 over the work is restricted to wasps and to large butter- 

 flies and moths. Small insects, even those as large as 

 houscflics and hcneybees are not strong enough to pull 

 the anthers, shaped like tiny saddle-bags, out of their 

 sheaths. To those insects the honey-filled and sometimes 

 actually honey-dripping milkweed flowers are like so 

 many baited traps, as deadly and remorseless to the hun- 

 gry insects as the steel traps of the fur hunter are to 



A WONDERFULLY BEAUTIFUL SPECIMEN 



This stately white pine was planted for shade and ornament near a city 



liome. 



bears and beavers. Their feet are caught on the specks 

 of sticky gum, which mark the joint of the two halves 

 of the saddle-bag anthers. Trapped in this manner they 

 are held prisoners until they die, and their shrivelled 

 bodies may be found on almost every patch of milkweeds. 

 One might think that the powerful bumblebee and the 

 milkweed would make ideal partners, but such is not the 

 case. These remarkable plants, which not only flow with 

 honey, but also invite their insect guests by a strong 

 honey scent, are utterly ignored by the big hungry bum- 

 blebee, who have, for some unknown reason, acquired a 

 passion for the purple of the clover and the blue of lobe- 

 lias and gentians ; although to the human observer, getting 

 honey out of these flowers seems a truly laborious task. 



The closed gentian, found 

 in bloom in this latitude 

 from the latter part of Au- 

 gust to the middle of Octob- 

 er, furnishes one of the 

 most remarkable cases of 

 adaptation of a flower to 

 bumblebees. The striking 

 whirls of beautiful sky-blue 

 flowers are evidently a 

 kind of bill-board advertise- 

 ment to bun''blebees. But 

 these magnificent blue flow- 

 ers, often made still more 

 conspicuous by being deli- 

 cately tipped with white 

 seldom open. Day and 

 night, in sunshine as well 

 as in rain and fog, they 

 remain tightly closed. Many 

 observers have been led to 

 conclude that this fine au- 

 tumn flower had abandon- 

 ed cross-pollination and re- 

 sorted to self-pollination ; 

 however, careful observa- 

 tion has convinced me that 

 such is not the case. The 

 bumblebees do get into 

 these closed gentians. In 

 fact, I do not think they 

 miss a flower on those 

 plants that grow in the open, where the gentians are not 

 hidden by tall grasses. 



With great care the hard working bumblebee selects 

 a flower that has not been pumped dry by a buzzing 

 competitor. Then, with his strong and long proboscis 

 he finds the opening in the closely folded floral segments. 

 With his head he pries the five segments apart and now, 

 literally standing on his head he kicks and pulls himself 

 with great effort into the blue honey well, until only his 

 defensive posterior and a pair of legs remain partly 

 visible, and if he is not a good sized bumblebee he dis- 

 appears altogether. I watched one on a sunny September 

 day, and I thought he worked harder than any other 



