Garden and Forest. 



[Number 202. 



except in the brilliant white bark which covers its old 

 trunks, and in its shorter cones with thicker scales. This 

 is the Pinus albicaulis, a low, stunted alpine tree of much 

 picturesque beauty as it appears at the edge of the timber- 

 line on Mount Shasta in California, but too small, scattered 

 and inaccessible to be of any economic value. 



Pinus Ayacahuite, a noble timber-tree, and the common 

 White Pine of northern Mexico, where it forms extensive 

 forests on high mountain-slopes, in a small cone-form 

 grows on a few of the ranges of southern Arizona. Re- 

 lated to this species, and often confounded with it, is a 

 second Mexican Pine and the last of our list of American 

 White Pines, Pinus Bonapartea, a tree of whose distribution 

 and value very little is known. 



A CORRESPONDENT writcs US from a village where an ener- 

 getic Improvement Society was established last spring : 

 " I'm afraid our people are overdoing the matter of tree- 

 planting. Every member seems to feel that it is incumbent 

 upon him to plant a tree somewhere, and usually a good 

 many. The work is not done with much care or system, 

 and I feel half-inclined to protest ; but so zealous are the 

 workers that I would probably be set down as an outlaw 

 if I objected. May I inquire whether you would ever con- 

 sider it advisable to discourage the planting of trees ? " 

 No one should ever plant a tree unless he is able to give a 

 good reason why it should stand in the place selected, 

 and unless he can tell why the tree he has chosen is prefer- 

 able to one of any other species for the spot. No tree of 

 any kind should be planted anywhere unless it is a healthy, 

 vigorous individual, and unless there is reasonable assur- 

 ance that it will be properly cared for in after-years. Pro- 

 fessor Beal has told us that of twelve memorial trees 

 planted with some official ceremony in Ann Arbor, not one 

 was found to have made satisfactory growth two years 

 later ; only one had received any cultivation — nearly all 

 were having an unequal struggle with grass, insects and 

 poorly prepared or thin and hungry soil. Tree-planting 

 of this sort is worse than a waste of time. Such an exam- 

 ple is bad in every way, discouraging, demoralizing. 



It is not an uncommon complaint among the newly 

 organized associations for village improvement that the 

 zeal of its members finds an outlet in excessive tree-plant- 

 ing. It is an easy thing to put the roots of a tree in the 

 ground, and then have it to look at with complacency as a 

 monument of our public spirit. The watchful care which 

 ought to follow, however, requires an unwavering deter- 

 mination, patience and study which do not always fol- 

 low sudden spurts of devotion to some popular movement, 

 and the trees languish. What is worse, the planters often 

 look on themselves with great approbation for what they 

 have done, and neglect to do anything else. One of the 

 very best societies of this sort in New England passed 

 through this experience, although the village now enjoys 

 thorough sanitary drainage, clean, well-sprinkled and well- 

 lighted streets, sidewalks kept in good repair, neat hitch- 

 ing-posts and public watering-trough, and a general trim- 

 ness and tidiness which are the direct outcome of the work 

 of this organization. All this necessary work was postponed, 

 and the united energy of the reformers vi^as devoted to plant- 

 ing trees, until so many had been set out that the removal 

 of a considerable portion of them became one of the plain- 

 est necessities in the improvement of the village. 



It is too often the case that those who have determined 

 to plant trees begin by studying descriptions in nursery 

 catalogues, and select a motley list of those which promise 

 to show some striking departure from those vi^ith which 

 they are familiar. They then wait until late planting-time 

 and send their orders ; and after the trees have come they 

 begin to search about for a place to put them. If it hap- 

 pens that too many have been ordered, or that few of them 

 are adapted to the position selected, they are hurried into 

 the ground and huddled together, and in a few years they 

 are objects of pity rather than of admiration. 



Crosses and Crossing of Plants. 



THIS was the subject of a paper read at the late meet- 

 ing of the Massachusetts State Board of Agricul- 

 ture by Professor L. H. Baile}', of Cornell University. The 

 paper is too long to reproduce entire, but we give in a con- 

 densed form what seems to us the most instructive part of 

 the argument. Professor Bailey's language is adhered to 

 in the main, but in some cases a paragraph is summarized 

 in a sentence, and in this way the original loses some of 

 its richness of illustration. 



Sex clearly has two offices : (i) To hand over, by some mys- 

 terious process, the complex organization of the parent to the 

 offspring ; and (3) to unite the essential characters or tenden- 

 cies of two beings into one. The second office is the greater, 

 for it insures an offspring somewhat unlike either parent, and 

 therefore better fitted to seize upon any place or condition 

 new to its kind. And as the generations increase, the tendency 

 to variation in the offspring must be constantly greater, be- 

 cause the impressions of a greater number of ancestors are 

 transmitted to it. If, therefore, the philosophy of sex is to 

 promote variation by the union of different individuals, it 

 must follow that greatest variation must come from parents 

 considerably unlike each other in their minor characters. 

 Thus it comes that in-breeding tends to weaken a type, and 

 cross-breeding tends to strengtlien it. 



In this discussion the term "cross" is used to denote the 

 offspring of any sexual union between plants, whether of dif- 

 ferent species or varieties, or even different flowers upon the 

 same plant. There are different kinds of crosses. One of 

 these is tlie hybrid, or a cross between two species, as a Plum 

 and a Peach, or a Raspberry and a Blackberry. Crosses be- 

 tween varieties of one species are termed " half-breeds " or 

 " cross-breeds," and those between different flowers upon the 

 same plant are called " individual crosses." Distinct species, 

 however, as a rule, refuse to cross. If we apply the pollen of 

 a Hubbard Squash to the flower of the common field Pump- 

 kin, the fruit will not form. The same is true of the Pear and 

 the Apple, the Oat and the Wheat, and most very unlike species. 

 Or the pollen may " take" and the seeds may grow, but the 

 plants which they produce may be wholly barren, sometimes 

 even refusing to produce eitlier flowers or seeds, as in the in- 

 stance of some hybrids between the Wild Goose Plum and the 

 Peach. Sometimes the refusal to cross is due to some differ- 

 ence in tlie time of blooming, or some incompatibility in the 

 structure of the flowers. But it is enough to know that there 

 are characters in widely dissimilar plants which prevent inter- 

 crossing, and that these characters are just as positive as are 

 size, color, productiveness and other characters. That is, the 

 checks to crossing have been developed through tlie principle 

 of universal variability and natural selection, just as other 

 characters have been established. The result is simply that 

 the best results of crossing are obtained when the cross is 

 made between different individuals of the same variety, or, at 

 farthest, between different individuals of the same species. 

 In other words, hybrids — or crosses between species — are 

 rarely useful, and it follows, as a logical result, that the more 

 unlike the species the less useful will be tlie hybrids. 



Again, crossing alone can accomplish little. The chief 

 power in the progression of plants appears to be selection. 

 Selection is the force which augments, develops and fixes 

 types. Man must not only practice a judicious selection of 

 parents from which the cross is to come, but he must con- 

 stantly select the best from among the crosses, in order to 

 maintain a high degree of usefulness and to make any ad- 

 vancement ; and it sometimes happens that the selection is 

 much more important to the cultivator than the crossing. I 

 do not wish to discourage tlie crossing of plants, but I do de- 

 sire to dispel the illusion which too often hangs about it. 



CROSSING STRENGTHENS EXISTING TYPES. 



The improvement of existing varieties by crossing is a more 

 important office than the summary production of new varie- 

 ties. This is the chief use which nature makes of crossing 

 — to strengthen the type. Think, for instance, of the great 

 rarity of hybrids or pronounced crosses in nature ! No doubt 

 all the authentic cases on record could be entered in one or 

 two volumes, but a list of all the individual plants of the world 

 could not be compressed into ten thousand volumes. There 

 are a few genera, in which the species are not well defined or 

 in which some character of inflorescence favors promiscuous 

 crossing, in which hybrids are conspicuous ; Ijut even here 

 the number of individual hybrids is very small in comparison 



