110 



THE GARDEN MAGAZINE 



November, 1915- 



Briefly the autumn metamorphosis is 

 effected as follows: 



At the approach of winter leaves which 

 cannot withstand frost cease their func- 

 tion as food factories, and the various food 

 substances are conveyed from the leaf- 

 blade into the woody branches or subter- 

 ranean rootstock and there stored, chiefly 

 in the form of starch, until the season of 

 growth re-commences the following spring. 

 The leaves from which everything useful 

 has been transported form nothing more 

 than a framework of cell -chambers con- 

 taining merely waste-products, like crystals 

 of calcium oxalate, which are thrown off 

 with the leaves and help to enrich the soil. 

 But while the process of food evacuation 

 is going on other changes take place. In 

 many plants a chemical substance known 

 technically as anthocyanin is produced 

 in the leaves, and often to such an extent 

 as to become plainly visible on the exte- 

 rior. It appears red in the presence of free 

 acids in the cell-sap, blue when no acids 

 are present, and violet when the quantity 

 of acids is small. In a great many leaves 

 the bodies which contain the green coloring 

 matter become changed to yellow granules 

 while the evacuation of food substances is in 

 process. Sometimes these granules are 

 very few and anthocyanin is absent; then 

 the leaf exhibits little out- 

 ward change except losing 

 its freshness before it falls. 

 In others the yellow gran- 

 ules are abundantly de- 

 veloped and if anthocy- 

 anin is absent, or nearly 

 so, the whole leaf assumes 

 a clear yellow hue. If 

 there is an abundance of 

 yellow granules together 

 with free acids and an- 

 thocyanin, the leaf as- 

 sumes an orange color. 

 Thus the leaf at the period 

 of autumnal change, by 

 the presence of these sub- 

 stances in a greater or 

 lesser degree, loses its 

 green hue and becomes 

 brown or yellow, crimson 

 or orange, purple or red. 

 The play of color is greater 

 according to the number 

 of species and individuals 

 associated together in a 

 particular spot. But the 

 greatest display of color is 

 seen when the neighbour- 

 hood is sprinkled with 

 plants having evergreen 

 foliage, when it often hap- 

 pens that a relatively 

 small area of woodland 

 and meadow appears 

 decked in all the colors of 

 the rainbow. 



The most casual ob- 

 server knows that all trees 

 and shrubs do not assume 

 tinted foliage in autumn. 

 Some, like the Alder, 



the Locust (Robinia), the Elder and most 

 Willows, exhibit little or no change save 

 perhaps a number of yellow leaves scat- 

 tered through the green before they fall. 

 But this group is relatively small and only 

 adds additional contrast to the landscape. 

 Again, plants whose leaves are covered 

 with silky or woolly hairs or with a felted 

 mat of hairs never present any autumn 

 coloring, and in those in which the green 

 color disappears the change is to pale gray 

 and white. 



In a rather large group of trees which in- 

 cludes the Walnut, Butternut, Catalpa, 

 Elm, Hickory, Chestnut, Horse Chestnut, 

 Linden, Button Tree, White Birch and 

 others, the tints are a general mixture of 

 rusty-green and yellow and Occasionally 

 pure yellow under favorable circumstances. 

 In the Poplar, Tulip Tree, Honey Locust 

 (Gleditsia), Mulberry, Maidenhair Tree 

 (Ginkgo), Beech and most of the Birches, 

 the leaves change to pure yellow of differ- 

 ent shades. In none of the above-men- 

 tioned groups is purple or red of any shade 

 developed. 



In favorable years the American or 

 White Ash (Fraxinus americana) is unique 

 in its tints passing through all shades from 

 a dark chocolate to violet, clear brown and 

 salmon but it has no reds. 



No deciduous tree surpasses the European Beech {Fagus sylvatica) for its foliage color at all seasons 



The Peach, Plum, Pear, Apple, Quince,. 

 Cherry, Mountain Ash (Sorbus), Hawthorn, 

 Silver Maple, Wild Roses and Brambles 

 (Rubus) have a predominance of green 

 with a slight or considerable admixture 

 of purple, red and yellow, and individuals 

 are frequently strikingly brilliant. In an- 

 other group purple, crimson and scarlet 

 with only a slight admixture of yellow, if 

 any, obtains. Here belong the Tupelo, 

 Scarlet Oak, White Oak, Poison Ivy, 

 Virginia Creeper, Sumach, Viburnum, Sor- 

 rel Tree, Cornel, Blueberries and many 

 other plants. A final group, to which be- 

 long the Red, Sugar, Striped and Mountain 

 Maples, Smoke Tree (Cotinus), Poison 

 Dogwood, Sassafras and the Shadbush 

 or Snowy Mespilus has variegated tints 

 comprising all shades of purple, crim- 

 son, scarlet, orange and yellow on the 

 same or different individuals of the 

 same species. Often the leaves are tinted 

 and sometimes figured like the wings of a 

 butterfly. 



Careful observers will note that the 

 gradations of autumn tints in all cases are 

 in order of those of sunrise, from darker to 

 lighter hues, and never the reverse. The 

 brown leaves which long persist on some 

 trees (Beech, Chestnut and certain Oaks 

 for example) , though darker than the yellow 

 or orange from which 

 they often turn, are no 

 exception since these 

 leaves are dead and the 

 brown is only assumed 

 after vitality has vanished. 

 Some species are per- 

 fectly uniform in their 

 colors; others, on the 

 contrary, display a very 

 wide range. For example 

 the Maidenhair Tree, the 

 Tulip Tree, and Birch are 

 invariably yellow ; the 

 Virginia Creeper, Sumach 

 and White Oak chiefly 

 red; while Maples are as 

 many colors as if they 

 were of different species. 

 But each individual tree 

 shows nearly the same 

 tints every year, even as 

 an Apple tree bears fruit 

 of the same tints from 

 year to year. 



The Red Maple {Acer 

 rubrum), so abundant in 

 swamp and wood, road- 

 side and on dry hill top, 

 is the crowning glory of a 

 New England autumn. 

 By the last week of August 

 it commences to assume a 

 purplish tint; sometimes 

 a solitary branch is tinted, 

 frequently the coloring 

 process begins at the top 

 of the tree and the pur- 

 ple crown of autumn is 

 placed on the green 

 brow of summer. Trees 

 growing side by side are 



