INTRODUCTION TO BOTANY. XXXI 



paper, and the name of the gemifi and Natural Order to which it belongs 

 written on the left-hand corner near the base. 



204. The most convenient size for the slieets of paper is 16 inches long 

 by 10^ wide. 



205. No more than one species should ever be fastened on one sheet of 

 paper ; but as many specimejis as will conveniently lit may be placed side 

 by side. 



206. The name, place of growth, soil, elevation above the sea, season of 

 flowering, colour of the flower, and if a shrub or tree, the height, nature 

 of the wood, etc. and any useful information respecting the species, and 

 not deducible fi-om the specimen, — should be written on an attached label 

 or on the sheet to which the spdcimen is fixed. 



207. The sheets of species arranged under their genera and Orders, are 

 kept in cabinets made with compartments to suit the size of the paper 

 used. 



208. When it is required to examine or dissect flowers or fruits that 

 have been dried, it is necessary to soften them. If the parts are very 

 delicate, this is best done by gradually moistening them in cold water ; 

 in most cases steeping them in boiling water or in steam, is usual, and is 

 much quicker. Very hard fruits and seeds will require long boiling in 

 order to dissect them easily. 



209. For dissecting and examining flowers in the field, a penknife and 

 a pocket lens of two or three powers, fi'om half an inch to two inches focus, 

 are sufiicient. At home it is more convenient to have a mounted lens or 

 simple microscope, with a stage holding a glass plate, upon which the 

 flowers to be dissected may be laid, and a pair of dissecting-knives, one of 

 which should be narrow and pointed, or a fine needle fixed in a handle ; 

 the other should have a pointed blade, with a sharp edge, to make clean 

 sections across the ovary. A compound microscope is rarely necessary, 

 except in cryptogamic botany. For the simple microscope, lenses of i, 

 :^, 14 inch focus are sufiicient. 



210. Many species vary within limits which it is very diflieult to express 

 in words. It may also happen that the specimen gathered may present 

 some occasional or accidental anomalies peculiar to that single one, or to a 

 very few individuals of the species. Hence the ditficulty constantly ex- 

 perienced by the young student, and not seldom by the more expert 

 botanist, of recognizing the various forms of a species by the technical 

 characters assig-ned to it in a Flora. It may be useful, therefore, to point 

 out a few of the anomalies likely to be met with, and we may di\dde them 

 into two classes, as follows : — 



1. Aberrations fi-om the ordinary type or appearance of a species^ fur 

 which some general cause may be assigned. 



A bright light and open situation, particularly at considerable ele- 

 vations or in high latitudes, vcdthout too much wet or drought, 

 tends to increase the size and heighten the colour of flowers, in 

 proportion to the statm-e and foliage of the plant. 



Shade, on the contrary, especially if accompanied by ricliness of soil 

 and sufiicient moisture, tends to increase the foliage and draw 

 up the stem, but to diminish the number, size, and coloui- of 

 the flowers. 



A hot climate and dry situation tend to increase the hairs, prickles, 

 and other productions of the epidermis, to shorten and stiflen 

 the branches, rendering thorny plants yet more spinous. Mois- 

 ture in a rich soil has a contrary eftect. 



The neighbourhood of the sea, or a saline soil or atmosphere, im- 

 parts a thicker and more succtilent consistence to the foliage 

 and almost every part of the plant, and appears not un- 



