April §, 1893.] 



Garden and Forest. 



153 



clumps are like a dash of the brush in a picture; l)ut it is a 

 blue no artist could ever render. This Alpine jewel, whose 

 presence no botanist mentions elsewhere in Europe than on 

 the high granite rocks of our mountains, is also found among 

 the Rocky Mountains of the United States, whence a friend, a 

 Swiss botanist, has brought me a specimen, which I have 

 carefully preserved. Dwarfed and low, turning to the sun its 

 masses of stemless flowers, which vary in tint from tf^nder to 

 deep rose color, side by side we find tlie Androsace glaciale ; 

 further on we see flie yellow of the sulphur-hued Saxi- 

 frage, S. aphylla, the carmine and purple of S.-oppositifolia, 

 and S. biflora, and other parti-colored plants, which form 

 a mass of rubies, as it were, sparkling on the mountain-side. 

 Such a unique, charming sight is well worth an annual pilgrim- 

 age to the higher regions. There one may truly say, " Terres- 

 tria sidera, flores." 



Geneva, Switzerland. -"• LorreVOH. 



Impotency of Pollen. 



THE investigations made by Mr. M. B. Waite, of the United 

 States Department of Agriculture, the results of which 

 were presented before the Western New York Horticultural 

 Society, have led to some interesting and valuable conclu- 

 sions. It has long been a mystery why certain trees and 

 orchards, growing apparently under favorable conditions in 

 every way, failed to yield satisfactory crops of fruit ; and 

 these studies suggest what may prove a solution in many 

 cases. The point which Mr. Waite tried to determine was the 

 efficiency of the pollen of fruit-trees on the pistils of the same 

 variety, and his experiments covered trials on the stigma of 

 the same flower, on another flower of the same cluster, on 

 one of a different cluster on the same tree, and on those of 

 different trees. The study of the effect on the ovule of the 

 same flower, and on those of the same cluster, was made, both 

 by simply covering the cluster with paper-bags and by hand- 

 pollinations. The hand-pollinations were made by removing 

 all flowers except the ones to be operated upon, emasculating 

 these before they opened, then keeping them carefully covered 

 with paper-bags and applying the desired pollen at the proper 

 time. The results are of especial value, because the number 

 of experiments was very large. The first were made in a large 

 orchard in Virginia, and as the season advanced the work was 

 continued in the orchards of Messrs. EUwanger & Barry, at 

 Rochester. It was found that a large number of our more 

 common varieties of Apples and Pears are nearly sterile when 

 reached only by pollen of the same variety. To make sure 

 that failure to fruit did not come from the method of manipu- 

 lation instead of the inefficiency of pollen, many crosses were 

 "made, subject to the same conditions as the individual polli- 

 nations, and summaries of the figures were given, to verify 

 the conclusions drawn. Observations showed that Pears 

 which did develop fruit by being impregnated with pollen of 

 the same variety, were generally different in shape from those 

 which were cross-fertilized, being less dilated toward the blos- 

 som end, where the seeds are borne. This points toward an 

 imperfect seed-development, even though the pollen had 

 sufficient potency to develop the fruit. If the attempt were 

 made to grow such seeds it would not be surprising to find 

 most of them unfertile. 



The varieties of Pears which the experiments thus far indi- 

 cate to be self-sterile, are Bartlett, Anjou, Clapp's Favorite, 

 Clargeau, Sheldon, Lawrence, Mount Vernon, Gansel's Berga- 

 motte, Superfin, Pound, Howell, Boussock, Louise Bonne de 

 Jersey, Souvenir du Congress, Columbia, Winter N6lis, Beurre 

 Bosc, Jones's Seedling, Easter and Gray Doyenntf. Those 

 which appear to be self-fertile are White Doyenne, Le Conte, 

 Kieffer, Duchess, Seckel, Buffum, Manning's Elizabeth, Flem- 

 ish Beauty and Tyson. 



Among Apples the following were found to be self-sterile : 

 Tolman Sweet, Spitzenburg, Northern Spy, Chenango Straw- 

 berry, Bellflower, King, Astrachan, Gravenstein, Rambo, Rox- 

 bury Russet, Norton's Melon and Primate ; while Codlin (par- 

 tially), Baldwin and Greening are self-fertile. 



The inefficiency of pollen in fertilizing flowers on the same 

 plant is well known among vegetables, a fact which presents 

 one of the chief difficulties in breeding new varieties. This is 

 well illustrated by experiments with Cucurbets, at Cornell Uni- 

 versity. In the season of 1889 there was found among the 

 many crosses being grown one Squash which appeared to 

 possess qualities which would render it valuable tor cultiva- 

 tion. The seeds of this were planted the following year, and 

 among the large number of plants thus produced there was 

 found just one, the fruit of which resembled that of the parent. 

 This was a discouraging outlook for that line of breeding, and 

 that year the attempt was made to fix this type by individual 



pollination. The earliest blossom had been crossed before the 

 character of the fruit was known ; this produced a perfect 

 fruit, but all those furnished with pollen from the same plant 

 grew for a brief time, withered and died. Other forms ap- 

 peared throughout the field which seemed desirable, but only 

 one plant of a type, so that crossing could not be resorted to, 

 and to plant all the seeds, with the expectation of a crop with 

 few or none like the parent, was out of the question. Indi- 

 vidual pollination was the only way, and this proved the same 

 in every case ; of the 185 flowers thus treated that year, not 

 one produced fertile seeds, although twenty-two carried fruits 

 through to maturity. It was a tantalizing effort to watch forms 

 more attractive than any in cultivation, apparently within the 

 grasp and yet so far from it. 



Hitherto this similar condition of affairs has not been sus- 

 pected in fruit-planting, especially the fact that pollen from 

 one tree may be unable to fertilize the blossom of other trees 

 of the same variety. The first thought is to account for this 

 latter fact by the much closer affinity of the same variety of 

 fruit than of the same variety of vegetable produced from 

 seed, owing to the very different physiological principles upon 

 which they are propagated. To account for the opposite be- 

 havior of different varieties of the same fruit is not so easy, but, 

 whatever may be the underlying cause, it will be of great in- 

 terest to note whether two plants of the same variety which 

 have been propagated from the same source, and under the 

 same climatic and other conditions, will behave toward each 

 other the same as two which have been subjected to very 

 different conditions, both in the present and past genera- 

 tions. 



The history of the Virginia Pear-orchard, which led to these 

 investigations, is an interesting one. Many years ago the 

 owner ordered a few trees of different varieties from a firm 

 in New York state. These being planted near together proved 

 so satisfactory that he ordered a large number of Bartletts 

 alone for a commercial orchard. These were planted in a sin- 

 gle block, and never bore satisfactory crops, with the excep- 

 tion of a few of the trees surrounding the original planting of 

 mixed varieties. The disappointment, owing to failure of the 

 undertaking, led to inquiries which brought about the present 

 investigations. Tlie orchard of EUwanger & Barry, on the 

 other hand, being largely of specimen trees, with but few of a 

 kind, presents just the opposite conditions, and is noted for its 

 productiveness. 



It has been well known that certain varieties of Raspberries 

 and Grapes have proved unproductive unless planted near 

 other sorts, but this has been attributed to a deficiency in the 

 amount of pollen produced. Closer observations may show 

 that in some cases it is due rather to a lack of potency than to 

 a lack of quantity. 



In the transactions of the Illinois Horticultural Society for 

 1886 a case is reported in which the behavior of the Dewberry 

 seems to bear on this point. One hundred plants were ordered 

 of a nurseryman and set by themselves. These grew vigor- 

 ously and blossomed full every year, but yielded only a few 

 imperfect berries. Later it so happened that a plot of Black- 

 berries were planted beside them ; when these came into bear- 

 ing the Dewberries began to fruit, and continued to do so regu- 

 larly. 



It is very evident that the practical lesson of these experi- 

 ments is an emphatic warning against planting orchards in 

 large blocks of a single variety, or planting isolated specimens 

 for family use. It may succeed, but the chances of failure are 

 far too great. rr j ur ^ j 



Cornell University. rred. IV. Card. 



Notes on the Forest Flora of Japan. — X. 



IN the last issue of these notes something was said of 

 two Maples (Acer pictum and Acer Miyabei) which in- 

 habit Yezo ; scattered through the forests of this island are 

 eight other species. Among them, growing only in the 

 extreme north and on the high slopes, is a variety of our 

 Mountain Maple, Acer spicatura, so like the New England 

 form of this common tree that it is difficult to distinguish 

 the two plants; Acer Tartaricum, var. Ginnala, a common 

 Manchurian tree, not rare in northern Japan, where it 

 grows in low, wet ground near the borders of streams, 

 and now well established in American gardens in which it 

 might be seen more often to advantage, as its flowers are 

 very fragrant and the leaves of very few trees take on more 

 splendid autumnal colors. In Yezo, too, Acer capillipes 

 has been found ; this is a species with small racemose 

 flowers and thin, delicate, nearly circular, lobed leaves, 



