For March, 1921 



519 



cultivation that to American gardeners seems fastidious and 

 finical, if not ludicrous, because of its refinement and expense. 



Our gardeners can not, of course, rely upon the dates and 

 various other matters which are governed by differences of 

 climatic conditions. But, besides finding such interesting reading 

 concerning the history of the various vegetables, they would be 

 encouraged to make experiinents with many excellent edibles as 

 yet unknown to them and some of which might find a permanent 

 place among garden delicacies in certain localities. This would 

 help the nation greatly toward winning its "way back to a simpler, 

 healthier food." 



The Roii.\xce of Ocr Trees, by Ernest H. Wilson; Doubleday. 

 Page and Company, Garden City, N. Y. 



It is opportune that this elegant work appears at a tiine when 

 trees have begun to be appreciated as in no other period. Even 

 before the Great War caused the sacrifice of much fine timber and 

 the mutilation, if not the destruction, of thousands of fruit trees 

 had forestry been receiving increasing attention in every civilized 

 land. Now the magazines and even the daily press, in this coun- 

 try and practically all over Europe, are awake and are rousing 

 people to the desirability and the need of planting new trees and of 

 protecting the old. "A nation's finest trees should rightly be 

 counted among its most prized national treasures ; but of the 

 countries of the world today Japan alone regards ancient trees 

 as a national treasure asset ! Such they truly are. and there is 

 no escape from the punishment Nature meles out to lands whose 

 forest growth is destroyed. In this country the price is being 

 exacted, and in countries like China and Korea the multiple in- 

 terest is so great that the lands groan beneath the burden. With 

 no trees to hold the soil on steep slopes when heavy rains fall. 

 rivers become charged with silt, break their bounds, destroy every- 

 thing within their reach — crops, villages and inhabitants." 



For writing the Romance of Our Trees there could be no better 

 equipment than that of Mr. Wilson, who has now often success- 

 fully explored those portions of the old world that are richest 

 in plants adapted to the conditions obtaining in the northern tier of 

 the .American states, and who, through connection with the 

 Arnold Arboretum, has been able there to study their adaptation 

 best. 



The chapter Our Nut Trees displays scholarly insight and 

 grasp of conditions combined to make good sense in treating of a 

 field in which vagaries are often disastrous. The chapter given to 

 the magnolias makes the reader wish, even if he had never 

 thought of it before, that he might have an arboretum of his 

 own in which to enjoy them to the full. The eulogy of the horse- 

 chestnuts is poetry fine enough to please the most fastitdious, who 

 might complain only that the red-flowering receive to little praise. 

 It might be complained also that the small flowering trees, the 

 cherries, the wild crabs, the pluins and the peaches, and the others 

 so appropriate for the shrubbery and the woods borders, do not 

 have bestowed upon them the honor vouchsafed to those already 

 named and to the Ginkgo, the Cedars, the Yews, the Beeches, the 

 Common Fruit Trees, the Poplars, the Willows, the Trees of 

 Upright Habit and the Pygmies. But of these the Cherries have 

 before been honored with a book all to themselves and if Mr. 

 Wilson were to write about the others, as it is to be hoped he may 

 soon do, they would need an additional volume. 



Most of the chapters have appeared in the Garden Magazine. 

 But the new prefatory chapters alone make the book well worth 

 while. Nowhere else could one be so impressed by the Ancient 

 Lineage of trees; nowhere else could one find so clearly set forth 

 the present-day distribution of trees ; nowhere else could one 

 learn so to marvel at the wonderful individuality of their rugged 

 trunks ; nowhere else could one prepare better to comprehend their 

 Autumn glorv. 



Prodittive Soils, by Wilbert Walter Weir, J. B. Lippincott 

 Company. Philadelphia. 



Designed originally for farmers the work, in its abridged edi- 

 tion as a volume in the valuable Farm Life Text Series, is in- 

 tended to serve not only as "a farmers' readv reference or prac- 

 tical guide in successful soil management," but also "for voca- 

 tional and other high school instruction" and "in secondary agri- 

 cultural schools atid vocational schools." With this last end in 

 view there are offered, at the end of each chapter, suggestions 

 for dcinonstrations and for laboratory exercises and home ex- 

 periments and projects. But it is a book that throughout is full 

 of instruction, clear, definite, accurate and impressive, for all 

 who may be concerned in any v.ay with the source, direct and in- 

 direct, of the supply of nearly cverythin.g that meets man's physi- 

 cal needs. The kitchen-gardener, the floriculturalist, the 

 horticulturalist, the nurseryman, the park superintendent and 

 the landscape .gardener can find much help, very much help, par- 

 ticularly in the part bearing the title Factors Determining Soi! 

 Fertility. Under this head are ranged chapters given to Soil 



Water and its Relation to Soil Fertility, Land Drainage and Irri- 

 sration. Tilth and Tillage, Soil Organisms in Relation to Soil 

 Fertility, Nitrogen, Phosphorus and Potassium in Relation to 

 Soil Fertility, Soil Acidity and Limmg in Relation to Soil Fer- 

 tility and Harmful Agents in Soils Affecting Fertility. All of 

 these subjects are handled with a completely satisfactory degree 

 of thoroughness and exhaustiveness that in every paragraph and 

 in every sentence reveal nice discrimination. Of these chapters 

 the one on drainage and irrigation is of especially general value, 

 and, to only a slightly less degree, the one on harmful agents af- 

 fecting fertility. The one named here last is perhaps tlie only 

 one in the entire book which might have been advisedly expanded 

 a little more. But it is a work devoted primarily to a study of 

 soils, a subject that though obviously so fundamental to success 

 in making plants grow well is too much oxerlooked, commonly, 

 liecause of easy faith in fertilizers and superiority of seeds or 

 in the excellent' condition, it may be, of the plant that is set into 

 the soil. 



As a volume of ready reference it is most laudable for the 

 evident perfection, as working instruments, of the Table of Con- 

 tents and of the Index. The general arrangement and the typing 

 correspond with the ?uthor's firm grasp and general mastery of 

 the subject matter. 



A LESSON ON PLANT PHYSIOLOGY 



(Contiiiucd from page 516) 

 made up of one part of oxygen and two parts of hydrogen; 

 while carbon dioxide consists of two parts oxygen and one part 

 carbon and all these elements enter into the structure of a carbo- 

 hydrate The elements of water and carbon dioxide ar separated m 

 the leaf' and recombined to form a carbohydrate, in which process 

 oxyo-en is a waste product and is given off by the working cells, 

 some of it being respired through the stomata and the remaiiider 

 used in other processes taking place in the plant cells. Ihe 

 process is made more clear by a consideration of the chemical 

 formula; involved. Carbon dioxide is composed of one part 

 carbon and two parts oxygen, the chemical formula of which is 

 CO=- while the formula for water is H,0. If we combine these 

 together we get H^COj, or two parts hydrogen, one of carbon, 

 and three of oxygen. The composition of a carbohydrate is 

 practically two parts hydrogen and one each of carbon and 

 oxygen (strictly speaking its formula is C.H.uOs) ; therefore the 

 combination of carbon dioxide and water contains two parts 

 more oxygen than is required for starch manufacture and is 

 therefore unused by the chlorophyll bodies, and is eliminated. 

 It is this fact which causes the respiration of plants in the sun- 

 light to be practically the inhaling of carbon dioxide and the 

 exhaling of oxygen, although only a part of this oxygen passes out 

 through the stomata into the air as some of it is diffused through 

 the pfant for the use of the protoplasm. This manufacture of 

 starch ceases in the dark, so that after sunset the interchange 

 of gases in the leaf, or respiration, no longer takes place— or 

 at least only to a very small extent— and oxygen is not, therefore, 

 exhaled by plants during the night. 



This brief sketch of the work carried on by leaves shows the 

 importance of giving each plant sufficient room for it to attain 

 its maximum leaf-development. Plants allowed to remain for 

 any length of time in an over-crowded state not only produce 

 weak foliage but the leaves are deprived by each other of light 

 and air. Thinning out when necessary should always be started 

 at the earliest possible moment, as the longer the period during 

 which plants are crowded together, the greater will be the harm 

 done to them, and the more difficult will be their recovery— if 

 such recovery ever takes place — to a condition of a. healthy, 

 luxuriant growth after they have had more room given them. 

 Not only must plants have space for proper development but 

 those in greenhouses, living rooms, etc., must be given the best 

 possible atmosphere environment. The fact that this environ- 

 ment in its fullest sense is practically impossible of attainment 

 in a dwelling house is the main reason why so few plants do 

 well there for any length of time. In this connection, however, 

 much may lie done to keep plants healthy by maintaining clean 

 foliage aiid by not allowing the stomata to become choked with 

 dust. Cleanliness of foliage is under all conditions one of the 

 first principles in successful plant culture. To this end attacks 

 of fungi and insects should be prevented, or at least never allowed 

 to make any material headway. 



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I Boston Spring Flower Show | 

 I Horticultural Hall | 



I Boston, April 6-10 j 



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