ib8 BOTANICAL WORK. [SECTION 19. 



way. It is well to make drawings or outline sketches of the smaller parts, 

 aud especially diagrams of the plan of the flower, such as those of Fig. 

 225, 'I'll, 241, 2ii, 275-277. For these, cross sections of the flower-hud 

 or flower are Lo be made : and longitudinal sections, such as Tig. 27U-27-A, 

 are equally important. The dissection even of small seeds is not difficult 

 after some practice. Commonly they need to he soaked or boiled. 



575. The right, appreciation of characters and terms used iu description 

 needs practice and calls for judgment. Plants do not grow exactly by 

 ride and plummet, and measurements must be taken loosely. Difference 

 of soil and situation are responded to by considerable variations, and other 

 divergences occur which cannot be accounted for by the surroundings, nor 

 l)e anticipated in general descriptions. Annuals maybe very depauperate 

 in dry soils or seasons, or very large when particularly well nourished. 

 Warm and arid situations promote, and wet ones are apt to diminish pubes- 

 cence. Salt water causes increased succulence. The color of flowers is 

 apt to be lighter in shade, and brighter in open and elevated situations. 

 A color or hue not normal to the species now and then occurs, which 

 nothing in the conditions will account for. A white -flowered variation of 

 any other colored blossom may alir/ii/x he expected; this, though it may be 

 notable, no more indicates a distinct variety of the species than an albino 

 would a variety of the human species. The numerical plan is subject to 

 variation in some flowers ; those on tlic plan of five may now and then vary 

 to four or to six. Variat ions of the outline or lobing of leaves are so familiar 

 that they do not much mislead. Only wider and longer observation suf- 

 fices to prevent or correct mistakes in botanical study. But the weighing 

 of evidence and tlie balancing of probabilities, no less than the use of the 

 well-ordered and logical system of classification, give as excellent training 

 to the judgment as the search for tlie fads themselves does to the observing 

 powers. 



4. SIGNS AND ABBREVIATIONS. 



57*5- For a full account of these, whether of former or actual use, see 

 "Structural Bofany " of the " Botanical Text Book," pp. 367, 392, as also 

 for the principles which govern the accentuation of names. It is needful 

 here to explain only those used in the Manuals and Floras of this country, 

 for which the present volume is an introduction and companion. They 

 are not numerous. 



577. In arranging the species, at least those of a lnr<je genus, the divi- 

 sions arc denoted and graduated as follows: The sign is prefixed to sec- 

 lions of the highest rank : these sections when they have names affixed to 

 them (as PBTTNTTS CERABUB) may be called subgenera. \Vlicn the divi- 

 sions of a genus arc not of such importance, or when divisions are made 

 under the submenus itself, the most comprehensive ones are marked by as- 

 terisks, * for the first, * * for the second, and so on. Subdivisions are 



