xxvi OUTLINES OF BOTANt. 



233. If the specimen be succulent or tenacious of life, such as a Sedum or an Orchis, it may 

 be dipped in boiling water all but the flowers. This will kill the plant at once, and enable it to 

 be dried rapidly, losing less of its colour or foliage than would otherwise be the case. /JiPFng 

 in boiling water is also useful in the case of Heaths and other plants which are apt to snea men 

 leaves during the process of drying. , ., • 



234. Plants with very delicate coroUas may be placed between single leaves ot very mm 

 unglazed tissue-paper. In shifting these plants into dry paper the tissue-paper is not to De 

 removed, but lifted with its contents on to the dry paper. 



235. The number of sheets of paper to be placed between each specimen or sheet of specimens, 

 wUl depend, on the one hand, on the thickness and humidity of the specimens; on the otner 

 hand, on the quantity and quality of the paper one has at command. The more and the better 

 the paper, the less frequently will it be necessary to change it, and the sooner the plants will dry. 

 The paper ought to be coarse, stout, and unsized. Common blotting-paper is much too tender. 



236. Care must be taken that the paper used is well dried. If it be likewise hot, all the better : 

 but it must then be very dry ; and wet plants put into hot paper will require changing very soon, 

 to prevent their turning black, for hot damp without ventilation produces fermentation and 

 spoils the specimens. 



237. For pressing plants, various more or less complicated and costly presses are made. JNone 

 is better than a pair of boards the size of the paper, and a stone or other heavyweight upon them 

 if at home, or a pair of strong leather straps round them if travelling. Bach of these boards 

 should be double, that is made of two layers of thin boards, the opposite way of the grain, and 

 joined together by a row of clenched brads round the edge, without glue. Such boards, m deal, 

 rather less than half an inch thick (each layer about 2J lines) will be found light and durable. 



238. It is useful also to have extra boards or pasteboards the size of the paper, to separate 

 thick plants from thin ones, wet ones from those nearly dry, etc. Open wooden frames with 

 cross-bars, or frames of strong wirework lattice, are still better than boards for this purpose, as 

 accelerating the drying by promoting ventilation. 



239. The more frequently the plants are shifted into dry paper the better. Excepting for very 

 stiif or woody plants, the first pressure should be light, and the first shifting, if possible, after a 

 few hours. Then, or at the second shifting, when the specimens will have lost their elasticity, 

 will be the time for putting right any part of a specimen which may have taken a wrong fold or 

 a bad direction. After this the pressure may be gradually increased, and the plants left from 

 one to several days without shifting. The exact amount of pressure to be given will depend on 

 the consistence of the specimens and the amount of paper. It must only be borne in mind that 

 too much pressure crushes the delicate parts, too little allows them to shrivel, in both cases 

 interfering with their future examination. 



240. The most convenient specimens will be made if the drying-paper is the same size as that 

 of the herbarium in which they are to be kept. 'J'hat of writing-demy, rather more than 16in. 

 by 10 Jin., is a common and very convenient size. A small size reduces the specimens ;^too 

 much, a large size is both costly and inconvenient for use. 



241. When the specimens are quite dry and stiff, they may be packed up in bundles with a 

 single sheet of paper between each layer, and this paper need not be bibulous. The specimens 

 may be placed very closely on the sheets, but not in more than one layer on each sheet, and care 

 must be taken to protect the bundles by sufficient covering from the effects of external moisture 

 or the attacks of insects. 



242. In laying the specimens into the herbarium, no more than one species should ever be 

 fastened on one sheet of paper, although several specimens of the same species may be laid side 

 by side. And throughout the process of drying, packing, and laying in, great care must be taken 

 that the labels be not separated from the specimens they belong to. 



243. To examine or dissect flowers or fruits in dried specimens 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 much quicker. Very hard fruits and 

 seeds will require boiling to be able to dissect them easily. 



244. For dissecting and examining flowers in the field, all that is necessary is a penknife and 

 a pocket lens of two or three glasses from 1 to 2in. focus. 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 may be laid ; and a pair of dissectors, one of which should be narrow and pointed, or a 

 mere point, like a thick needlej 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 cryptogamio botany and vegetable anatomy. For the simple microscope, lenses of J, 

 J, 1, and IJin. focus are sufficient. 



245. To assist the student in determining or ascertaining the name of a plant belonging to a 

 Flora, analytical tables should be prefixed to the Orders, Genera, and Species. These tables 

 should be so constructed as to contain, under each bracket, or equally indented, two (rarely three 

 or more) alternatives as nearly as possible contradictory or incompatible with each other, each 

 alternative referring to another bracket, or having under it another pair of alternatives further 

 indented. The student having a plant to determine, will first take the general table of Natural 

 Orders, and examining his plant at each step to see which alternative agrees with it, will be led 



