55 
withdrawn from the cell-walls, and freezes in the cavities of. the 
cells. Owing to loss of water from the cell walls, the cells shrink, 
and a crack is the result. When the temperature rises the cell- 
walls re-absorb the water, causing the cells to expand, and the crack 
closes more or less. The subsequent formation of callus completes 
branches each. When the branches of the upper tier were about 
forty years old, each one was injured by a severe frost-crack through- 
out its entire length. These wounds never completely healed, as 
shown in the accompanying photograph (fig. 3), and afterwards no 
more shoots were produced on these branches, the result being a- 
scarcity of leaves, which resulted in the crown of the tree being 
literally starved to death, owing to lack of food and water. The 
lower tier of branches, being sheltered by the upper ones, was 
perfectly healthy, and carried an abundance of foliage and flowers 
when the tree was cut ii 
in preventing rapid thawing. ; 
n the case of frost-cracks or injury caused by hail, the wounded 
parts should be sprayed with Bordeaux mixture at intervals until a 
callus is formed, 
mix 4 eee : ; 
impracticable, a thorough spraying with cold water is often effective 
IX.—LALANG GRASS. 
(Imperata arundinacea, Cyril). 
J. M. Hiviier. © 
Attention has recently been drawn to this plant as a source of - 
paper-making material. It is a common plant in tropical countries — 
and has been described as a pestilent weed, which once allowed to : 
invade a plantation, can only be eradicated at enormous expense ; ‘ 
it is ubiquitous, always one of the first weeds to cover newly opened : 
land, and by far the most difficult to eradicate, Bree as 2 
_Imperata arundinacea proper has a creeping rootstock with solid) = 
stems of 1 to 3 ft. and glabrous or bearded nodes, leaves erect, often 
