May 22, 1889.] 



Garden and Forest. 



249 



tion available in this country, to do otherwise than call all 

 forms with purple and white Howers varieties of M. Soulattgeana, 

 and drop the other names. 



A hybrid of more recent appearance and of doubtful orig-in 

 is in some respects the most interesting of the whole series. 

 This is the plant known in gardens as Magnolia Lenne. Van 

 Houtte, who published a colored plate of the Howers twenty 

 years ago, took it for granted that it was a hybrid between M. 

 conspiciui and M. obovata. He states, without further explana- 

 tion, that it originated accidentally in Lombardy, where it was 

 discovered by the nursery gardener. Turf of Erturt, who intro- 

 duced it into Germany, naming it in honor of Lenne, the Royal 

 Garden Inspector at Berlin.* The origin of this plant is not as 

 apparent as that of M. Soulattgeana, however — that is, it is not 

 as clearly intermediate in characters between its two supposed 

 parents. It is shrubby rather than arborescent in habit, with 

 wide-spreading stems branching from the ground. The 

 branchlets are much smaller than those of the other Magnolias 

 of this class ; the leaves are larger than those of the other spe- 

 cies, they are broadly ovate or sometimes slightly obovate and 

 pointed at the summit, but quite destitute of the short con- 

 tracted point found in those of M. conspicua and of M. Soii- 

 langeana. The Howers are the largest of the series, three and 

 a half to four inches deep, with colored petaloid obovate se- 

 pals about one-half the size of the petals, which are broadly 

 obovate, rounded at the extremities, fully four inches across, 

 deep dark purple over the whole of the exterior surface, and 

 pure snowy-white in the interior. The anthers are deep and 

 the anthers paler purple. The Howers are deliciously fragrant, 

 and the fruit and seeds, which are produced in profusion, are 

 larger than those of either of the supposed parents. Magnolia 

 Lenne might very well pass for a very robust, large-flowered 

 variety of M. obovata were it not for the petaloid sepals and the 

 broadly obovtite petals, which point to the blood of M. con- 

 spicua, and a probable hybrid — a solution which, however, 

 is not altogether satisfactory. 



Magnolia gracilis of gardens I have never seen, but, judged 

 by the Hgure in Hooker's " Paradisus Londinensis" (A Ixxxvii.), 

 it is nothing more than a slender form of M. obovata. 



The handsomest of the Magnolias with precocious flowers, 

 and the finest of the genus, with the exception, perhaps, of the 

 evergreen, M. grandiflora, of our southern forests, is M. 

 Ccimpbellii, a large forest-tree, peculiar to the mountain valleys 

 of Sikkim and Bhotan, at elevations of 8,000 to 10,000 feet. The 

 flowers are white or rose-colored and eight or ten inches 

 across. This species is apparently difficult to manage, 

 although it has been cultivated for many years in different 

 parts of Europe. It has flowered in a garden near Cork, in 

 Ireland, where this tree is fairly hardy, biit in northern Italy it 

 has so far, I believe, failed to produce flowers, and I have not 

 heard of it blooming elsewhere. It is hardly probable that it 

 has been introduced into the United States, although, owing to 

 the more humid summer climate, it might be expected to 

 flourish in some parts of the Gulf States perhaps better than in 

 southern Europe. 



May 8tli. C. S. S. 



Principles of Physiological Botany, as Applied to 

 Horticulture and Forestry. 



XX. — Injuries and Maladies. 



(Conclusion of the Series.) 



/^NE of the severest accidents with which any of our young 

 ^<^ trees can meet is girdling or "ringing." The removal of 

 a ring of bark from the stem does not at first appear to affect 

 the vigor or freshness of the plant, because, at the outset, 

 the upward supply of water is not cut off. During this 

 period of apparent resistance to the injury an attempt is made 

 by the tree to heal the wound by a growth of bark over it. If 

 the ring is not too wide, it is possible to repair the injury by 

 such a growth, but usually the younger, outside, wood of the 

 stem is invaded by decay, the water-supply is more or less 

 completely arrested, and then the tree yields. There are 

 numerous instances of remarkable vitality in trees, by which 

 they have been able to live, after a fashion, for many years, 

 after they have been girdled. One of the most recent records 

 of this kind attributes to a common Pine a lease of life for fif- 

 teen years after complete ringing. The account as given in 

 the Canadian Record of Science for October, 1888, is very 

 remarkable, and presents some features which cannot be 

 readily understood. Examples of the survival of Orange and 

 Olive trees, after serious injuries of this kind, are not rare. 



Freezing, followed by rapid thawing, may be numbered 

 among the most troublesome of the mechanical injuries to 

 plants. It is well known that many species of plants in ourcli- 

 mate are capable of Ijeing frozen and rapidly thawed many 

 tinies in a single season witliout sulfering any apparent injury, 

 whereas there are tender species of exotics which are n-repara- 

 bly injured by being subjected to a temperature near, but not 

 below, freezing. The difference between sudden and slow 

 thawing of a frozen part can be seen by a simple experiment 

 upon living plant-hairs placed for examination under a micro- 

 scope. If the work is done with sufficient care, the protoplasm 

 in tlie plant-cells can be completely frozen, and a separation of 

 the watery parts of the living matter from its more solid con- 

 stituents can be produced. This can be followed by a thawing 

 so slow, and a repair so perfect, that the protoplasm will again 

 assume its former character, and, when the proper tempera- 

 ture is reached, the motion which belongs to it normally is 

 seen to begin again. Now, in certain instances, the freezing 

 injures the cell-walls and the delicate protoplasmic lining, 

 whereas in others the walls are not apparently harmed in any 

 way. In the case of woody plants there is reason to believe 

 that the water in some of the parts beneath is not frozen even 

 when subjected to an extremely low temperature, but the sub- 

 ject has not yet been thoroughly examined under conditions of 

 careful experiment. In such an unusual season as our present 

 winter has been at the North, it is evident that harm results 

 from the freezing which is sure to follow the partial starting of 

 buds in mid-winter. Such injuries come under the general 

 head of what is known as winter-killing, but there are others 

 which are more obscure and are not easily explained in the 

 same way. A few of them, for instance the killing of ever- 

 greens in some winters, and their complete immunity in 

 others, can be understood upon the view that the process of 

 evaporation of water from the leaves goes on even in cold 

 days in winter, when from the cold ground little or no water 

 can be supplied to the roots to take its place. But there are 

 still some instances of the sort which cannot be yet understood. 



The nature of the injury produced by lightning has been 

 studied in the case of a few species of trees. Usually part of 

 the stem is torn in such a way as to indicate that some of the 

 water lodged in tlie woody tissues had been suddenly con- 

 verted into steam, and by the expansion has shattered them. 

 It does not appear that any tree is exempt from lightning. 



Maladies of Nutrition.— These belong rather to under- 

 feeding than to over-feeding, although there are marked in- 

 stances of the latter. Generally the lack of some mineral matter 

 essential to a fertile soil is shown by a general dwarfing and 

 unsatisfactory growth. The problem is not exceeded in com- 

 plexity by any which falls luider the observation of cultivators. 

 Even the distance of a few rods on the banks of some rivers 

 makes a diflerence in the bouquet of wine from grapes in ad- 

 jacent vineyards. In some of these cases chemical analysis 

 fails to detect differences in the character of the soil sufficient to 

 account for these differences in the character of the grapes from 

 precisely the same variety. Nor can it be a matter of expos- 

 ure to the rays of the sun, nor any other one factor yet sug- 

 gested. This is, however, an extreme case. In our own 

 country there is known to be a difference in the character of 

 the tobacco grown on a virgin soil and on an exhausted one 

 which has been artificialh- restored to its former fertility. 

 Larger and stronger plants can be raised on the fertilized soil, 

 but the wished-for delicacy of leaf and flavor cannot, as a rule, 

 be again obtained. 



That the suljject presents peculiar difficulties is illustrated 

 by the disease known as peach-yellows. According to some 

 assiduous investigators, this complex affection is due in part, 

 at least, to an insufficiency of potash salts in the soil, which 

 causes an undue accumulation of starch in certain parts and 

 an irregular distribution in others. But there are other com- 

 petent students of the subject who regard the malady as 

 attributable to the agency of micro-organisms. F"rom' the 

 principal facts bearing on this group of allied subjects, which 

 is of paramount importance to every cultivator of plants, 

 the reader is referred, with confidence, to works by Johnson* 

 and by Storer.f in which the topic is treated with fullness and 

 clearness. 



It is to the experiment stations in this countrv and abroad 

 that we must look for the solution of the many difficult and 

 important questions of a similar nature remaining unsettled 

 in the departments of Physiological Botany and \^egetable 

 Pathology. Under the liberal governmental grants made for 

 the purpose of supporting research in this field, stations have 



* The best figure of M.ignolia. L-nn^ w'M be found in 'ih.e Revue Horticole i8 

 /. 33. 



* How Crops Grow, and How Crops Feed. 

 t Agriculture. 



