. Lessons with plants. Suggestions for seeing and interpreting some of the common forms of vegetation. FiG. in birch leaves. serrate; 33, doubly - crenate; 34, cartilaginous; 35, acutely-erenate;36, obtusely-crenate; 37, plicate; 38, erenate; 39, crisped; 40, ob-tuse; 41, acute; 42, acuminate; 43, obtusely - acuminate; 44, emar-ginate acute. Suggestions.—We have said (127) that the forms of leaves aredescribed by comparing them with purely arbitrary measures. Weshould not expect them always to match these measures; in illus-tration of which, let the pupil cut the form of any leaf
. Lessons with plants. Suggestions for seeing and interpreting some of the common forms of vegetation. FiG. in birch leaves. serrate; 33, doubly - crenate; 34, cartilaginous; 35, acutely-erenate;36, obtusely-crenate; 37, plicate; 38, erenate; 39, crisped; 40, ob-tuse; 41, acute; 42, acuminate; 43, obtusely - acuminate; 44, emar-ginate acute. Suggestions.—We have said (127) that the forms of leaves aredescribed by comparing them with purely arbitrary measures. Weshould not expect them always to match these measures; in illus-tration of which, let the pupil cut the form of any leaf in paper. 122 LSSSOJVS WITS PLANTS and then endeavor to match it in other leaves. He will soondiscover how difficult it is to describe a leaf with accuracy, andhe will also apprehend the greater truth that there are probablynot two leaves alike. XXII. VARIATION IN PLANT, AND ONTHE SAME KIND. Fig. 119Variable leaves of smilu. LEAVES ON THE SAMEDIFFERENT PLANTS OF 134. The two bii-chleaves (Fig. 118) are fromthe same tree. They differin size, shape, and denta-tion (or toothing). There was also a difference incolor and in season ofmaturity. Now, let thepupil gather many leavesfrom one plant, and deter-mine if he can find anytwo of them alike. Hewill recall our studies ofthe buds and branches,and will be inclined toconclude that there is uni-versal difference in themembers of plants. 135. The live oakbranch in Fig. 77 will now VARIATION IN LEAVES 123 have new interest. The leaves upon the older (orlower parts) are normally entire, but the upper-most ones are distinctly sinuate. A different type
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Keywords: ., bookauthorbai, bookcentury1900, bookdecade1900, booksubjectbotany
