8o 



Garden and Forest. 



[February 13, 1889. 



treated in the same way as the commoner kinds, and, being 

 a gross feeder, will be benefited by occasional waterings of 

 liquid manure. F. Goldrins. 



Kenwood, N.Y. 



Plant Notes. 



The Origin of the Double-flowered Horse-chestnut. 



AS it seems very desirable to put on permanent record the 

 ■^~*- origin and history of curious forms and garden varieties 

 of cultivated trees, I have thought that the following resume 

 of an article which was published in the Belgique Horticole so 

 long ago as 1854 should be given in Garden and Forest. 

 Neither Loudon nor any other writer whom I have consulted 

 appear to have been aware of the facts mentioned below. As 

 the work to which I am indebted for the information is not 

 generally accessible to lovers of trees, a brief statement of the 

 real facts of the case can hardly fail to be of interest. 



The editor of the Belgique Horticole, in an early number of 

 that periodical for 1854, stated, in the letter-press accompanying 

 a very good figure of the Double-flowered Horse-chestnut, that 

 the origin of the form was unknown. Shortly afterwards. Mon- 

 sieur Auguste-Napoleon Baumann, nurseryman, Bollwiller, 

 wrote to the editor that the tree in question originated as a 

 branch-sport in the garden of Monsieur Duval, at Geneva, at 

 which town the writer stayed from 1819 to 1822, studying 

 botany under De Candolle. M. Baumann had noticed a 

 branch of the parent tree clothed with larger and more 

 deeply-colored leaves than usual ; he called the attention of 

 the gardener to this particular branch, and the following 

 spring when the tree was in flower, M. Baumann was sent for 

 to see it. That portion of the tree which had excited his 

 curiosity the previous year was laden with splendid inflores- 

 cences in which the stamens were changed into petals— the 

 flowers had become double. Grafts were sent to the famous 

 Alsatian nursery, and probably the vast majority of the speci- 

 mens now in cultivation have been propagated from the stock 

 raised at Bol wilier, in 1822. 



A writer in a recent volume of the Revue Horticole calls 

 attention to the hardiness of the tree, and M. Charles Baltet, 

 in his paper " De V action dufroid siir les vegeiaux," definitely 

 states that the Double-flowered Horse-chestnut did not suffer 

 in France during the very severe winter of 1879-80. 



Kew, January, 1889. George Nicholson. 



Monsieur Naudin contributes to the Revue Horticole an 

 account of two interesting new plants. The first is his Saccia 

 elegans, a name bestowed upon a shrubby plant of the Convol- 

 vulus Family, raised from seeds sent to Antibes by Dr. Sacc, 

 an agricultural chemist residing at Cochabamba, in Bolivia. 

 Unlike most Morning Glories, it is an erect shrub, growing to 

 a height of six feet or more ; the flowers are lilac, and hang in 

 long clusters from near the extremities of the branches. This 

 very ornamental plant is not hardy in the south of France, 

 although in Algeria it succeeds admirably, and has ripened 

 seeds. It may be expected to flourish in some parts of south- 

 ern California. 



Monsieur Naudin's second novelty is Sicana odori/era, a re- 

 markable Cucurbitaceous plant from Brazil, with climbing stems 

 twenty-five or thirty feet long, attaching themselves to the 

 smoothest surfaces by means of tendrils, theendsof which flat- 

 ten out and present an exceedingly adhesive surface to any 

 object with which they come in contact. This plant is monoe- 

 cious, with yellow flowers, which, when fertilized, producecylin- 

 drical fruits the size of a large Cucumber, or of a small Musk 

 Melon, and becoming red or'orange when fully ripe. They are 

 edible, although many persons dislike them on account of their 

 strong aromatic odor. Thev are used, it is said, to free dwell- 

 ing-houses of flies, which are unable to support their peculiar 

 odor. 



The Sicana requires more heat than the Cucurbitaceous plants 

 in common cultivation. It produced two fruits, however, at 

 Antibes the past season, in spite of the abnormally cold and 

 wet season, and M. Naudin believes that in an ordinary 

 season it would fruit abundantly. These fruits, although fully 

 grown, did not entirely ripen, and unless M. Naudin can suc- 

 ceed in ripening them artificially, further experiments with 

 this interesting plant must be deferred until a fresh supply of 

 seed can be obtained from its native country. M. Naudin 

 believes that the region in which this plant can be cultivated 

 can be extended by selection. " I have just spoken," he says, 

 " of the possibility of obtaining, sooner or later, variefies of the 

 Sicana better suited to our climate than the plants first intro- 

 duced. Whether it is considered the result of acclimatization 

 or not, the fact remains that the constitution of the exotic Cu- 



curbitaceous plants which we have cultivated for a long time in 

 our gardens has been sensibly modified. The plants which 

 I have raised from the seeds of species brought from the 

 tropics have been invariably more difficult to raise and later in 

 ripening their fruit than individuals of the same species raised 

 from seed produced in France, and adapted, to a certain ex- 

 tent, by long cultivation to their surroundings. It is to be 

 hoped, therefore, that the same change may be operated with 

 the Sicana, and perhaps with several other species." 



It is probable that the long summers of our Southern States 

 will make the cultivation of this very interesting, and perhaps 

 valuable, plant possible there. 



Principles of Physiological Botany as Applied to 



Horticulture and Forestry. 



VII. — Nitrogen. 



A LL living matter (protoplasm) contains a certain propor- 

 ■^"^ tion of nitrogen in combination — the living matter of 

 animals is derived directly or indirecfly from the living matter 

 of plants, and, therefore, the appropriation of nitrogen by the 

 latter is a question of great importance and general interest. 



By far the larger proportion of the nitrogen appropriated 

 by plants is absorbed in the form of some combination. 

 Experiments on an extensive scale, and very carefully con- 

 ducted, have been correctly interpreted as showing that, un- 

 der the conditions of_ the experiments-in question, none of the 

 nitrogen absorbed came from that which exists, uncombined, 

 in the atmosphere. But there are certain facts in regard to the 

 nutrition of a few plants which render it highly probable that, 

 under some circumstances, the free nitrogen of theatmosphere 

 may be udlized to some extent as a source of this element. 

 While, therefore, the general statement found in the text- 

 books — namely, that the nitrogen of plants is not obtained 

 from the free nitrogen of the air — is undoubtedly correct in the 

 main, it should be qualified to some extent for at least a few 

 of our cultivated plants. It is necessary to consider first the 

 general statement, and pass thence to the puzzling exceptions. 



In the experiments instituted to setfle this vexed question, 

 series of plants were cultivated under conditions by which 

 they were afforded all the materials necessary for healthy nu- 

 trition, with the sole omission of combined nitrogen. These 

 trials were made in numerous ways, and with every possible 

 precaution, but always with the result of showing that the 

 plants growing in our ordinary air did not derive there- 

 from any of the free nitrogen. It is seldom that experiments 

 in any field of research are checked by as many precautions 

 to avoid error as characterized the series referred to, and 

 therefore the results have been generally and properly 

 accepted. 



The forms of combination most favorable as nitrogenous 

 food for plants are different for different plants ; for instance, 

 for some, the ammonium salts are best, while for some others, 

 nitrates serve a better purpose. The following statement 

 presents briefly the general facts relative to this point : The 

 Beet and Tobacco thrive best when combined nitrogen is 

 afforded them in the form of ammonium salts, and the same 

 is true of the Sunflower. But, usually, nitric acid, in any of 

 its diffusible combinations, answers every purpose. These 

 combinations may be with ammonium, potassium, sodium, 

 calcium and magnesium. It may be said that, as a rule, these 

 combinations offered to the plant must not present an alkaline 

 reaction, but there are some exceptions to this. 



Whence do our wild plants obtain in nature their supply of 

 these substances, which, of course, our agricultural and horti- 

 cultural plants procure from the liberal amounts presented to 

 them in the form of mariures ? Leaving for subsequent con- 

 sideration the question of utilizing, in some cases, the free 

 nitrogen of the air, it may be said that the supply appears to 

 come first, from the minute amount of combined nitrogen 

 present in the air and brought down in falling moisture. 

 These combinations are in very small amount, and are prop- 

 erly termed traces, since, the minute quantity cannot be 

 accurately determined. By electrical disturbances in the 

 atmosphere, combinations of the free nitrogen, with oxygen 

 on the one hand and with hydrogen on the other, are effected. 

 A second source is probably the nitrogen which enters into 

 combination during the evaporation of water at certain tem- 

 peratures. A third source is found in the products which 

 result when organic matters, perhaps in a state of decay more 

 or less complete, are acted upon by weak electrical currents. 

 This may possibly explain, in part, the good effects of vegeta- 

 ble mold incorporated with the soil. 



At this point should be noticed, in passing, the important 



