For July, 1922 



199 



to feel. So is the beauty of the formal garden felt, so 

 prevalerit in certain parts of the East. 



It is freedom from conventionality, rather than freedom 

 from restraint, that characterizes all tnie Californians. 

 It is this spirit which is reflected in California gardens. 

 In the extreme East the spirit which prevails is that of 

 "yon must do this and you mustn't do that ; observe all 

 of the proprieties ; do not deviate an inch from the ac- 

 cepted line of traditional conduct." Here in the West we 

 are tempted to go to the other extreme — to break away 

 entirely from established precedent and custom. But 

 there is an obvious danger in this attitude, which must 

 be guarded against in matters of gardening. 



In California, therefore, the trend is towards a distinct 

 informality in most of the plantings. And yet, even in 

 informality there must be some semblance of unity of 

 purpose and conception — in fact, it is really much more 

 difficult to form an inforn.ial or naturalistic garden, than it 



is to construct a formal garden. Sometimes the wisest 

 l.)rocedure seems to be to strike a happy medium between 

 the two — to include the best features of the formal gar- 

 den, giving them an intimate setting. In other words, 

 we remove the austerity of too fonnal a treatment, by 

 adding a touch here and there of informality. 



It is conceivable that California will some day develop 

 a style of landscape gardening peculiarly her own. In 

 the California garden will be revealed the spirit of the 

 California landscape, coupled with an expression of the 

 feelings and sentiment of the true Calif ornian. Ideas 

 borrowed from styles of gardening in vogue in other 

 regions, which can be utilized to advantage, will be in- 

 corporated in the garden, but certain features of the 

 garden will breathe the atmosphere of California. 



The illustration on the front cover shows the century- 

 old live oaks (Onerous agrifolia) on the campus of the 

 University of California, Berkeley. 



Bark and Its Uses 



WILLARD N. CLUTE 



A 



Ll, plants, save the very simplest, are protected 

 from the external world by a resistent covering 

 commonly known a; bark. This might he truth- 

 fully described as the plant s skin for like the skin of ani- 

 mals, it is renewed from a softer underlying tissue and 

 is constantly thrown off or worn away from the surface. 

 In both animals and plants the outermost layer is known 

 as the epidermis, but the deeper layers, especially in 

 plants, have diti'erent names. 



Bark is commonly formed by two different layers of 

 growing cells known as cambium cells. The activities 

 of the outer layer produce the corky bark w'hile a deeper 

 layer gives rise to the other tissues associated with the 

 cork cells. This latter layer has a second important func- 

 tion for. in addition to building up the bark, it annually 

 adds a new layer to the woody cylinder. The patterns 

 of the bark, which alone are often sufficient to identify 

 the species, are due to peculiarities in the growth of the 

 cork cambium, but it is the ever-increasing pressure from 

 the growing cyliu'ler of wood that causes the bark to 

 crack along the lines marked out by the cork cambium. 

 Thus is produced the papery bark of the birch, the splin- 

 tery back of the hickory, the flaky bark of the sycamore 

 and the furrowed bark of walnut and oak. 



In most woody plants the layer of cork is spread rather 

 uniformly over the stem, but in the sweet gum and in 

 some species of the elm and cuonymus, certain regions 

 of the cork cambium are more active than others and 

 this results in a number of cork ridges or wing's running 

 lengthwise of the stem. In the cork oak, the corky bark 

 is so well developed that it forms a layer several inches 

 thick. If this is carefullv removed, the cork cambium 

 will produce a new layer of cork in a few seasons. All 

 our bottle corks are derived from this source. The dark 

 streaks seen in the corks are openings through which 

 the living cells transpire. On young twigs these open- 

 ings appear as tiny specks or lenticels. 



The cork cells not only protect the plant from me- 

 chanical injury and the attacks of fungi, but owing to 

 the minute air spaces they contain, they also modifv the 

 effects of sudden changes of temperature w^hich are so 

 tryin.g to plants. The inner layers of bark are composed 

 of strong fibers, known as phloem or bast. From these 

 fibers is sprung most of the thread, twine and cordage 



used for a multitude of purposes in the commercial 

 world. 



It is well known that if a ring of bark is removed from 

 I stem the stem dies, but this is not due, as so many as- 

 sume, to shutting off the water supply of the plant. It is 

 true that there are a series of small tubes in the bark, 

 luit these do not carry water and food materials upward. 

 Instead th.'^y carry the food elaborated in the leaves to all 

 parts of the plant. Removing a ring of bark from the 

 stem, therefore, stops the supply of food to the roots and 

 the plant slowly starves to death. That food is carried 

 downward in the bark is apparent when one notices how 

 greatly the stem is swelled above any constriction about 

 it. In plants like the grape where the fruiting branches 

 are renewed annually, the branches are sometimes ringed 

 to prevent the escape of the manufactured food which 

 thus remains to increase the size of the fruit. 



Although we commonly give more thought to the wood 

 of plants than to the bark, the latter is of such great im- 

 portance that it may be questioned which is the more 

 valuable. The bark seems to be a favorite place for stor- 

 ing elaborated materials by the plant. In many cases 

 these are in the nature of waste products so far as vege- 

 tation is concerned, but they find a wide use in human 

 economy. From the milky juice or latex in the bark of 

 numerous tropical trees and vines most of the rubber and 

 gutta-percha is obtained. A still larger number in all parts 

 of the world yield the tannins so useful in turning hides 

 into leather. Fixed oils are rarely obtained from barks, 

 but there is a long list of essential oils derived from this 

 tissue, familiar instances of which are the oils of cinna- 

 mon, sassafras and birch. A large number of the alka- 

 loids and related substances used in medicine are also 

 taken from barks, quinine, is possibly the best known of 

 these substances. In addition there are produced from 

 barks, numerous dyes. gums, varnishes and other sub- 

 stances that are found useful wherever the arts of man 

 flourish. 



Think about yourselves, about what you want, what 

 you like, what respect people ought to pay to you, what 

 people think of you. and then to you nothing will be 

 pure. May God keep our hearts pure from that selfish- 

 ness which is the root of all sin ! — Charles Kingsley. 



