86 



THE GARDENERS' MONTHLY 



[March, 



that this part was covered by ice at about the end 

 of the past century. This being so, it becomes a 

 matter of considerable interest to ascertain how 

 so many plants have maintained an existence 

 here — whether they have appeared since the re- 

 cession of the ice, or whether they managed to re- 

 tain their hold during the whole continuance of 

 the ice-sheet. 



At our landing place a small stream entered the 

 ocean, and this stream came through a swampy 

 valley a few hundred feet wide, extending into the 

 land for an unknown distance. The hills of drift 

 were on each side of this valley. All the plants 

 were collected within a quarter of a mile of the 

 mouth of this stream, and there is every reason to 

 believe that a larger number of species might 

 have been collected had there been time or oppor- 

 tunity for more inland research along its line. By 

 the margin of the swamp were rocks from five to 

 ten or twenty feet above its ground level, and not 

 covered by drift ; but on the more level rocks 

 often with a few feet of sand, which had evidently 

 blown in during the course of years. Yet with 

 every opportunity to do so had there been time for 

 the work, very few of the plants along the line of 

 the stream had extended to the drift deposits close 

 by. These plants were not brought there by the 

 drift. We may say almost with certainty that they 

 were there during the period when the land was , 

 covered by ice. How did they manage to main- 

 tain themselves under these circumstances? 

 Were they wholly covered by the ice ; or were 

 there rifts and clefts in the ice-sheets deep enough 

 to allow plants a summer of recuperation ? 



I think we need not regard the last consideration 

 as one of necessity. There is reason to believe 

 that under a low temperature plants will retain 

 vitalpower for an indefinite period. Mr. Douglas, 

 of Waukegan, Illinois, once sent to me young 

 trees of Catalpa speciosa. that had been placed in 

 sand in a cool cellar and forgotten a year, and ' 

 that remained the whole twelve months dormant, 

 and grew the next year when planted out. Dr. 

 Maxwell T. Masters, of London, has called at- i 

 tention to the case of an orchid which, as I re- 

 member, remained under ground a whole season 

 without growing, and thiS' has been adduced as a 

 probable explanation of the non-appearance in 

 some seasons of plants which are plentiful in 

 others. If a plant will remain dormant one, two 

 or three years under unfavorable conditions for 

 growth, who shall say how much longer a period 

 they may not live, under conditions favorable to 

 dormancy only ? I have a strong suspicion that 

 just at or below the freezing-point, roots may live 

 for an unlimited number of years ; and that a 

 district might be covered by an ice-sheet for a 

 quarter of a century or more, and the plants be- 

 neath retain full vital powers. 



By referring again to my remarks on some i 

 geological features of this part of Alaska {page 

 183, Proc. Ac, as cited), it will be seen by a 

 sunken forest of apparently modern trees there is 

 reason to believe that in comparatively recent 

 times this peninsula was clothed with a rich vege- ; 

 tation— that it was of a sudden partially sub- i 

 merged and perhaps as suddenly elevated again a I 



little — and that all these changes have been the 

 work of but a few hundred years. The plants in 

 question have probably survived through all these 

 changes, though perhaps wholly ice-covered at 

 times, and have not been brought here by modern 

 agencies ; and if these suggestions, which are 

 offered only as great probabilities, should get fuller 

 confirmation from any one in the future who may 

 have opportunities of going more fully into an in- 

 vestigation of the spot, it will give additional 

 interest to the study of botany in connection with 

 the great changes which have been going on over 

 the surface of our globe. 



From other botanical evidences which south- 

 eastern Alasjca affords, I am inclined to believe 

 that geological changes in this section have not 

 required the long periods to effect which geolo- 

 gists usually demand. In the vicinity of the 

 Davidson Glacier, a little below Pyramid Harbor, 

 layers of ice may be seen covered by sand and 

 earth, and prevented from rapid thawing — only an 

 occasional spot showing the icy bed beneath — and 

 yet alder and other plants grow within a few 

 hundred yards. On the other hand, near the 

 Muir Glacier, at the point where the river-bed 

 beneath the ice diverges from the glacier's direct 

 course, the only sign of arborescent vegetation is 

 from a few score of willow-bushes, scattered on 

 the mountain-side. Beneath the drift, hundreds 

 of feet below, is a forest buried as it grew. Pines, 

 alders, and similar plants spread so readily in this 

 region, that these bare hill-sides would assuredly 

 be clothed thickly with a forest vegetation, thus 

 replacing the forests which have been swept away, 

 if there had been time enough for the purpose. 

 The immense area and great depth of these tree- 

 less drift formations would surely be regarded as 

 requiring perhaps many centuries for deposit, but 

 for the evidence which the botanical observations 

 afford that the whole change must have taken 

 place within very recent times." 



Immediate Influence of Pollen on Fruit. 

 — A leading pomologist, himself of great exper- 

 ience in crossing and hybridizing, writes : " When 

 it can be shown that a long variety of a cu- 

 cumber can, by immediate crossing, be made to 

 produce a short one, or a crook-necked squash be 

 transformed into one of turban form, then I shall 

 have more confidence in the new theory. " 



[Our correspondent makes a good point. So far 

 as squashes, pumpkins and melons are concerned, 

 there is not the slightest evidence that they have 

 been immediately changed by the pollen of an- 

 other variety. The " theory" is not exactly new. 

 Some gentleman communicated to the Royal 

 Horticultural Society of London, in the early part 

 of the century, a paper, showing that a netted 

 melon had produced smooth fruit as well on the 

 same plant. This was assumed without the sha- 

 dow of proof, to be from immediate action of pol- 

 len, — but we now know that changes in netting. 



