VEGETABLE THYSIOLOGY. 9 



pots until returning growth in the spring has been resumed, and the 

 young shoots have ^attained an inch in lieight. I then divide them, 

 inserting four plants into a 54-sized pot, placing them close to the 

 edn-e, and using precisely the same compost as for Gloxinias; when 

 i)otte'd I set them in the warmest part of the stove as near the glass 

 as possible, where, with attention to watering, frequent syringing, &c., 

 thev "-row very fast, and in three weeks or a month the pots become 

 filled'^with their roots ; they are consequently at once removed into 

 the pots in which thev are to bloom, some into 32's, others into 24's 

 and 12's, as occasion 'may require. In shifting at this time I sepa- 

 rate the plants, retaining equal portions of the ball to each, and place 

 them about an inch from the sides of the larger pot ; this not only 

 enables the roots to shoot with greater vigour into the fresh soil, but 

 afibrds ample room for the growth of the lateral shoots, and their 

 arrangement by tying, &c. When the flower-buds become prominent, 

 the pfants are remov'ed into the greenhouse to bloom, where, having 

 more air, they develope their flowers with greater perfection than in 

 the stove, and continue for a longer time to enliven the house by 

 their beauty. 



VEGETABLE PHYSIOLOGY. 



THE STEMS AND LEAVES OF PLANTS. 

 BY J. TODD, DENTON GARDENS, LINCOLNSHIRE. 



The roots of plants, with their functions, having been described in a 

 previous article (pages 215-217, vol. xiv.), the stems and leaves 

 come next under consideration. The stem, in its most usual form, is 

 that of a cylindrical column, diff"ering from the root in its tendency to 

 seek light and air, and in its being the immediate seat of those beau- 

 tiful appendages, the leaves and flowers. The leaves are flat expan- 

 sions of the cortical integument or bark, from which, however, in 

 European plants, they are mostly articulated, and after the lapse of a 

 few months fall awav, others in due time being produced from those 

 buds which are always developed in their axils. In bulbs, grasses, 

 and all flowerless plants, the leaves have no distinct point of separa- 

 tion, being only disengaged from the parent structure by putrefaction. 

 The stem serves as a sort of conduit, through which the moisture ab- 

 sorbed by the roots is transmitted to the leaves ; it also serves to 

 elevate the latter into the most favourable position for receiving the 

 full influence of light, heat, and air, (a circumstance in plant culture 

 of much importance,) the presence of which is indispensable to the 

 perfect consummation of their function, viz., the conversion of the 

 crude and watery fluid imparted to them into an inspissated and 

 nourishing sap. 



In making a transverse section of a branch or stem of any ot our 

 ordinary trees or shrubs, such as the common Hazel (Corylus Avel- 

 lana) for example, we perceive it to consist of three distinct parts, 

 usually known as pith, wood, and bark. The pith arises from the 

 collar, or that point which separates the root from the stem, and 



