. Plant studies; an elementary botany. Botany. r/'io. 334. Section across a young twig of box elder, showing the four stem regions: e, epidermis, represented by the heavy bounding line; c, cortex; w, vascular cyl- inder; p, pith.—Prom "Plant ; eter of woody stems (Fig. 335, w), and a possible increase of the branch system and foliage dis- play each year. (3) Leaf veins form- ing an open system (Fig. 333, figure to right). The network of smaller veinlets between the larger veins is usually very evident, especially on the under surface of the leaf, suggesting the name "n
. Plant studies; an elementary botany. Botany. r/'io. 334. Section across a young twig of box elder, showing the four stem regions: e, epidermis, represented by the heavy bounding line; c, cortex; w, vascular cyl- inder; p, pith.—Prom "Plant ; eter of woody stems (Fig. 335, w), and a possible increase of the branch system and foliage dis- play each year. (3) Leaf veins form- ing an open system (Fig. 333, figure to right). The network of smaller veinlets between the larger veins is usually very evident, especially on the under surface of the leaf, suggesting the name "net-veined'• leaves, in contrast to the " parallel-veined " leaves of Mono- cotyledons. The vein system ends freely in the margin of the leaf, forming an " open ; In consequence of this, although the leaf may remain entire, it very commonly be- comes toothed, lobed, and divided in various ways. Two main types of venation may be noted, which influence the form of leaves. In one case a single very prominent vein (rib) runs through the mid- dle of the blade, and is called the midrib. From this all the mi- nor veins arise as branches (Fig. 336), and such a leaf is said. Fig. 335. Section across a twig of box elder three years old, showing three annual rings, or growth rings, in the vascular cylinder; the radiating lines (m) which cross the vascular region (?/;) represent the pith rays, the princi- pal ones extending from the pith to the cor- tex (c).—From " Plant ;. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Coulter, John Merle, 1851-1928. New York, D. Appleton and Company
Size: 1622px × 1540px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorcou, bookcentury1900, bookdecade1900, booksubjectbotany
