The American botanist and florist; including lessons in the structure, life, and growth of plants; together with a simple analytical flora, descriptive of the native and cultivated plants growing in the Atlantic division of the American union . rather than ribs ? 283. Define Midvein. What leaf has such ? De-fine vein, as in Maple. Veinlets. Veinulets. 284. Name and describe the Venation ofthe Exogens—Of the Endogens—Of the Ferns. 285. What leaf is pinni-veined? —Palmi-vemed ?—Tripli-veined ? Parallel venation how varied ? CHAPTER XXI. MORPHOLOGY OF THE LEAF CONTINUED. 287. That infinite variet
The American botanist and florist; including lessons in the structure, life, and growth of plants; together with a simple analytical flora, descriptive of the native and cultivated plants growing in the Atlantic division of the American union . rather than ribs ? 283. Define Midvein. What leaf has such ? De-fine vein, as in Maple. Veinlets. Veinulets. 284. Name and describe the Venation ofthe Exogens—Of the Endogens—Of the Ferns. 285. What leaf is pinni-veined? —Palmi-vemed ?—Tripli-veined ? Parallel venation how varied ? CHAPTER XXI. MORPHOLOGY OF THE LEAF CONTINUED. 287. That infinite variety of beautiful and graceful forms forwhich the leaf is distinguished, becomes intelligible to the stu-dent only when viewed in connection with its venation. Sinceit is through the veins alone that nutriment is conveyed for the 96 STEUOTUEAL BOTANY. develoi^ment and extension of the parenchyma, it follows thatthere will be the greatest extension of outline where the veinsare largest and most numerous. Consequently the form of theleaf will depend upon the direction of the veins and the vigorof their action in developing the intervening tissue. In accord-ance with this theory, leaf-forms wdll be classed in respect totheir Forms of leaves^.—311, Rhododendron maximum. 312, Alnns glutinosa (cult.). 313, Polygonum sagit-tatum. 314, Pawpaw. 315, Impatiens fulva. 316, Celtis Americana. 317, Circsea Lutetiana. 318,Catmint. 319, Solidago Canadensis—a tripli-veined leaf. 288. Feather-veined leaves. Of these, the followingforms depend upon the length of the veinlets in relation to eachother and to the midvein. ~When the lower veinlets are longerthan the others, the form of the blade will be (1) ovate, with theoutline of an Qgg, the broad end at the base; (2) lanceolate, orlance-shaped, narrower than ovate, tapering gradually upward;(3) deltoid, or triangular-shaped, like the Greek letter A. 289. If the middle veinlets exceed the others in length, the leafwill be (4) o
Size: 2009px × 1243px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1870, booksubjectbotany, bookyear1870
