300 



ARBORETUM AND FRUTICETUM. 



PART III. 



astiingent. '* The spines of the common berberry are a curious state of leaf, 

 in which the parenchyma is displaced, and the ribs have become indurated. 

 The}^, as well as all the simple leaves of ordinary appearance, are articulated 

 with the petiole, and are therefore compound leaves reduced to a single foliole ; 

 whence the supposed genus Mahonra does not differ essentially from Berberis 

 in foliage any more than in fructification." {Linclley, Introcl to N, S., p. 31.) 

 The species are generally thorny, and most of them flower freely in spring, 

 bearing fruit abundantly in autuinn. 



The irritability of the stamens of the genus Berberis, and more par- 

 ticularly of those of the common berberry, of B. canadensis, B. sinensis, 

 and, perhaps, of all the species the flowers of which expand, is a very 

 remarkable property, which was first discovered by Kolreuter ; probably 

 from observing that the stamens were put in motion by the proboscis of 

 insects extracting honey from the flowers. Sir James Edward Smith has 

 given a copious account of this phenomenon in the Phil. Trans., vol. Ixxviii. 

 p. 158., and the last, and most clear and concise, description of it will 

 be found to be that by Dr. Lindley, under the article Berberis, in the Petmi/ 

 Cychpcedia. The stamens, " when the filament is touched on the inside with 

 the point of a pin, or any other hard instrument, bend forward towards the 

 pistil, touch the stigma with the anther, remain curved for a short time, and 

 then partially recover their erect position. This is best seen in warm dry 

 weather. After heavy rain, the phenomenon can scarcely be observed, 

 owdng, in all probability, to the springs of the filaments having been already 

 set in motion by the dashing of the rain upon them, or to the flowers having 

 been forcibly struck against each other. The cause of this curious action, 

 like that of all other vital phenomena, is unknown. All that has been ascer- 

 tained concerning it is this, that the ii-ritability of the filament is affected 

 differently by different noxious substances. It has been found by Messrs. 

 Macaire and Marcet, that, if a berberry is poisoned with any corrosive agent, 

 such as arsenic or corrosive subHmate, the filaments beco-me rigid and brittle, 

 and lose their irritability; while, on the other hand, if the poisoning be effected 

 by any narcotic, such as prussic acid, opium, or belladonna, the irritability is 

 destroyed by the filaments becoming so relaxed and flaccid, that they can be 

 easily bent in any direction. It is difficult to draw from this curious fact any 

 other inference than this, viz. that in plants, as well as in animals, there is 

 something analogous to a nervous principle, which is more highly developed 

 in some plants, or in some organs, than in others." {Fen. Cyc, iv. p. 260.) 

 According to Sir J. E. Smith, the purpose of this remarkable function in the 

 stamens of the berberry is evident. " In the original position of the stamens 

 the anthers are sheltered from rain by the concavity of the petals. Thus, 

 probably, they remain till some insect "comes to extract honey from the base 

 of the flowers, and, thrusting itself between the filaments, unavoidably touches 

 them in the most irritable part; and thus the impregnation of the germs is 

 performed." {Phil. Tra/ZA-., Ixxviii. p. 158.) All the species are easily propa- 

 gated by seed, which most of them produce in abundance; those which do not 

 are readily increased by the removal of their side suckers, or by layers. They 

 will grow in any soil, though they mostly prefer one that is calcareous. 



Though the species of this genus are commonly treated as shrubs, and these 

 shrubs, from their numerous side suckers, have, in general, a rough, inelegant 

 appearance ; yet there are some of them which may be formed into the most 

 beautiful and durable small trees that can be introduced into gardenesque 

 scenery. The common berberry, when pruned up to a single stem to the 

 Jieight of 8 ft. or 10 ft., and all suckers from the root, and all side buds from 

 the stem remoA-ed the moment they appear, will form a fine orbicular head 

 with the extremities of the branches drooping ; and this pendulous appearance 

 will increase with the age of the tree. Such'a tree, covered, as it wilfbe every 

 year, with yellow blossoms in the beginning of summer, and with bright scarlet 

 fruit in autumn, may rank in beauty and value with the low trees of the genera 

 C'ratas^gus, Cotoneaster, and Ameldnchicr. 



