xlviii INTRODUCTION. 



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 2 inches 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 needle, in a handle ; the other should have a pointed blade, with 

 a sharp edge, to make clean sections across the ovary. A compound micro- 

 scope is rarely necessary, except in cryptogamic botany and vegetable anatomy. 

 For the simple microscope, lenses of i, -J, 1, and 1J inches focus are sufficient. 



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

 belonging to a Flora, analytical tables are in this work prefixed to the Orders, 

 Genera, and Species. These tables are 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 in- 

 dented. The student having a plant to determine, w 7 ill first take the general 

 table of Natural Orders, and examining his plant at each step to see which al- 

 ternative agrees with it, will be led on to the Order to which it belongs, he w T ill 

 then compare it with the detailed character of the Order given in the text. If 

 it agrees, he will follow the same course with the table of the genera of that 

 Order to find the genus, and again with the key of the species of that genus to 

 find the species. 



Suppose the plant to be a Dandelion, a Daisy, or a Thistle. On opening 

 what appears to be the flower, we see at once that each part, which we may at 

 first have taken for a petal, contains a separate style, and has a separate ovary 

 (appearing like a seed) under it, but no separate calyx, all these florets being 

 collected within a common involucre. The flower is therefore compound. Our 

 attention is also called to the anthers. They may at first escape the beginner, but 

 with a little care they will be discovered forming a ring round the style. We 

 may then conclude that our plant agrees with the first alternative which refers 

 to the second bracket. We must now look to the ovary under any one of the 

 florets, cut it open, and, finding but a single ovule or seed, we are referred to the 

 great Order of Composites. This second bracket is only necessary to exclude 

 two or three Campanulaceous plants {Phyteuma and Jasione), which have the 

 united anthers and heads of flowers of Composites, but are most readily known 

 by the numerous small ovules or seeds in their ovary or fruit. On turning to 

 the description of the Order Composites, we are cautioned against confounding 

 with them two or three other plants which have similar heads of flowers, and 

 being satisfied we are right, we proceed in the same manner to find out the 

 genus of our plant. 



Suppose the plant to be a Violet. Although the anthers are united in a ring, 

 the flowers are quite separate, each with its own calyx, and we are referred by 

 the second alternative to the third bracket, the double perianth refers us to the 

 fifth, the free ovary to the sixth, the single ovary to the seventh, the irregular 

 corolla to the forty-first, the spur to one of the petals to the forty-second, the 

 five stamens to the forty-third, under which the five sepals and petals indicate at 

 once the genus Violet. We then compare our plant with the description of 

 the genus in the Flora, before we proceed to ascertain the species. In making 

 use of these descriptions, the beginner must be careful not to be misled by the 

 popular meaning of terms to which a technical sense has been given by botanists, 

 and in all cases of doubt he should refer to the definitions through the Index 

 of Terms. 



