The Natural System of Botany. 207 



off about a week afterwards, in order to throw all the 

 th into the bud. If, however, the operation be deferred 

 Str *l August or September, the head of the stock is generally 

 UI J. t j|i s pring. All the shoots below the bud should be rub- 

 bed or pinched off as soon as they appear. 



Magazine of Gardening. 



THE NATURAL SYSTEM OF BOTANY. 



MOM BEX SE YEW. 



Order — Viol ace m. The Violet Tribe. 



After Cruciferse, in the natural arrangement, come several 

 orders, which comprise but few genera, and those of no great 

 interest. Passing by these, we come to a small, but interesting 

 order, which contains some well known and favorite plants. 

 This 'is the order Violaceae, the Violet Tribe. To study its 

 structure, take the common garden Violet, or Heartsease, 

 Viola tricolor, which is easily obtained, and the parts of which 

 are larger and more readily examined than those of most other 

 species. The leaf is narrow, oblong, and undivided. At its 

 base are a pair of large, sessile stipules, deeply cut, and these 

 give the leaf the appearance of. being lobed. The sepals of 

 the calyx are five, of unequal size, and prolonged at the base. 

 The petals are also five, unequal, and two of them stand 

 upright, so as to appear above the others, and a third has a 

 horn or spur at its base. The stamens are also five, without 

 filaments. Two of them have long projections which are hid- 

 den in the horn of the petal, and they are all terminated by a 

 membranous expansion. The ovary is superior and one-celled, 

 with three parietal placentae, covered with young seeds. There 

 is but one style, in one side of which is an aperture leading to 

 the stigma. The reason of this peculiarity has not been 

 explained. The calyx is persistent, and the fruit to which it 

 adneres, after the other parts of the flower are gone, opens into 



