158 



CASSELL'S POPULAR GARDENING. 



of the Primulas and some 

 of the Campaniilas require 

 to he re-planted amiually, 

 or they will become leggy. 

 Remove all past flowering 

 stems promptly, unless it is 

 •desired to save seed. Take 

 care that the stronger-grow- 

 ing plants do not encroach 

 upon the weaker growers. 

 We once lost the loveliest 

 clunp of Gentiana verna we 

 evei saw in a garden, hy 

 the rapid growth of a mossy 

 Saxifrage during a few 

 weeks' absence from home. 

 It is simply astonishing how 

 soon the work of extermi- 

 nation is done. Of course 

 the best plan is to care- 

 fully avoid placing rapid 

 growers in the neighbour- 

 hood of any of the less 

 robust plants. During the 

 spring and summer months 

 pay great attention to water- 

 ing, so as to insure that no 

 plant suffers from drought. 

 If a speU of hot, dry 

 weather sets in, it wOl be 

 a. wise precaution to give 

 a surfacing of cocoa-nut fibre 

 after watering. This will pre- 

 serve the efficacy of the water- 

 ing for a considerable time. 

 Keep a sharp look-out after slugs 

 and predaceous insects. When a 

 plant has overgrown its position, 

 reduce its proportions with 

 promptitude, or it wiU hurt its 

 neighbours. Never allow weeds 

 any quarter. If these directions 

 are intelligently followed, it wUl 

 be found that a large proportion 

 of the Alpine plants of temperate 

 climes may be successfiJly gi'own 

 in most English gardens. 



rig. 42.— Simple Toothed Leaf of the Lime-tree, 

 showing ttie stallc and the blade. 



Pig. 43.— Divided or Lobed Leaf of 

 Batdunia. 



THE LIFE-HISTOEY OP PLANTS. 



By Dk. Maxwell T, Masteiis, F.E.S. 



HUTEITION: TEE LEAVES AND WEAT THET DO. 

 ri"^HE most important organs of the plant, so far as 

 JL its nutrition is concerned, are the roots and the 

 leaves. The roots, as we have seen, take from the 



soil the greater part of the 

 water required by the plant, 

 they absorb the mineral 

 and earthy matters, espe- 

 cially the nitrates. Their 

 chief, and sometimes only, 

 field of operation is the soil. 

 All this has been told in 

 preceding chapters. The 

 leaves take from the air the 

 greater part of the gases 

 required to feed and build 

 up the plant, and possibly 

 some of the water. In addi- 

 tion to this, the leaf is the 

 great laboratory, or factory, 

 in which the substances 

 taken in by the root, as well 

 as by its own exertions, are 

 blended and modified so as 

 ultimately to serve as food 

 for the plant, to build up its 

 substance, fabricate its cell- 

 walls and its protoplasm, 

 form and store away the 

 starch and other ingredients 

 which render the organs of 

 reserve so important to the 

 plant. In doing all this ii; 

 absorbs some gases and gives 

 out others ; it throws off 

 superfluous water and, under cer- 

 tain conditions, absorbs it. Much 

 of its work can only be accom- 

 plished .under the influence of 

 solar light. The work that it 

 does in common with the root and 

 other organs of the plant it can 

 do irrespective of Hght, provided 

 heat, moisture, and other condi- 

 tions be suitable ; but the special 

 work of the leaf, which we shaE 

 have to consider in this section, 

 can only be done when the leaf is 

 exposed to light, and what is true 

 of the leaf is true of all parts of 

 plants that are green in colour, 

 such as the young shoots or the 

 unripe fruit. 

 The ITature of Leaves. — In botanical lan- 

 guage, everything that bears a leaf is a stem or 

 a branch of a stem. The root is not a stem, because 

 it bears no leaves ; the tuber of a Potato or of a 

 Jerusalem Artichoke is a stem, because it does bear 

 leaves — not necessarily fully-developed leaves, for 

 they may be mere unformed scale-leaves. The 



