88 THE GARDENER. [Feb. 



mal. Adventitious leaf -buds may be produced from any part of the 

 medullary system, or wherever cellular tissue is present. Leaf-buds 

 universally originate in the horizontal or cellular system, and are 

 formed in the root, among the wood, and at the margin or on the sur- 

 face of leaves, whether perfect or rudimentary. Regular or normal 

 leaf-buds are only found in the axils of leaves, where they exist in a 

 developed or undeveloped state. Practically speaking, leaf-buds are 

 the means which nature has provided for supplying shrubs and trees 

 with leaves and branches in autumn. Deciduous trees lose their 

 leaves ; but in the axil of each a little bud previously forms, from 

 which fresh leaves are to expand the following spring. During winter 

 the bud is enveloped in numerous imperfect leaves or scales, which 

 are imbricated — that is, laid over one another like the tiles of a house. 

 This envelope is termed hyhernaculum, because it serves for the win- 

 ter protection of the young and tender portions of the buds. The 

 scales, though generally thin, are of a close membraneous texture, well 

 suited to exclude the cold : in many cases they are also covered with 

 a kind of gum. With the return of spring, when the sap becomes 

 heated, or rather when the sap becomes faster in its circulation, the 

 scales open and roll back, or in some cases fall off, to allow of the ex- 

 pansion of the true leaves that lie within them, curiously folded up 

 round a kind of stem called the axis or growing point, which, as the 

 leaves unfold, gradually elongates, and finally becomes a branch. 



In the Beech and Lime the outer scales of the leaf -buds are brown, 

 thin, and dry ; in the Willow and Magnolia they are downy ; in the 

 Horse-chestnut and the Balsam Poplar they are covered with a gummy 

 exudation. 



Flower-buds are produced in a similar manner to those described 

 above, from which they differ chiefly in containing one or more incipi- 

 ent flowers within the leaves — the flowers being wrapped up in their 

 own floral leaves, or bracts, within the ordinary leaves, which have 

 their outer covering of scales. The growing-point is generally devel- 

 oped when the leaves expand, but it is short and stunted, and unlike 

 the branches produced from the leaf-buds. Every flower-bud, as soon 

 as formed in the axil of the old leaf, contains within itself all the rudi- 

 ments of the future flowers. If a bud be gathered from a Lilac or 

 Horse-chestnut very early in spring, all the rudiments of the future 

 leaves and flowers will be found within it, though the bud itself may 

 not be more than half an inch long, and the flowers not bigger than 

 the points of the smallest pins. W. Robeets. 



PAKAFFIN-OIL A CURE FOR MEALY-BUG. 



I WAS a little surprised to find such a noted plant-grower as Mr Ham- 

 mond recommending in the ' Gardener ' for November the utter 

 destruction of plants of Hoya carnosa infested with mealy-bug ; and 



