. Fundamentals of botany. Botany. 230 STRUCTURE AND LIFE HISTORIES relatively narrow (from J4 to J^ inch), several feet in length, and interrupted at frequent intervals by swellings or nodes, which are air sacs, and add greatly to the buoy- ancy of the plant in water (Fig. 172). Many of theFucacese possess two kinds of branches, more or less distinct from each other—long branches and short branches, or spurs. This is a phenomenon which occurs in several groups of plants,. Fig. 173.—Ascophyllum nodosum (L) Lejol. Radical longitudinal sec- tion of an old branch of the thallus. c, cortical tissue
. Fundamentals of botany. Botany. 230 STRUCTURE AND LIFE HISTORIES relatively narrow (from J4 to J^ inch), several feet in length, and interrupted at frequent intervals by swellings or nodes, which are air sacs, and add greatly to the buoy- ancy of the plant in water (Fig. 172). Many of theFucacese possess two kinds of branches, more or less distinct from each other—long branches and short branches, or spurs. This is a phenomenon which occurs in several groups of plants,. Fig. 173.—Ascophyllum nodosum (L) Lejol. Radical longitudinal sec- tion of an old branch of the thallus. c, cortical tissue, the seat of photo- synthesis; m, central tissue, or medulla. (After Reinke.) and notably in the pines, to be studied later. In Ascophyll- um the distinction between long and short branches is not as strongly marked as in some other forms, such, for ex- ample, as Scaberia. The short branches have enlarged tips, which somewhat resemble the swellings of the main stem. The plant has a "rubbery" appearance, with a smooth, slippery surface, and is usually attached to rocks by a "hold-fast" organ. 209. Anatomy.—A study of the internal structure (Fig. 173) reveals two systems of tissues, more or less clearly distinct:. 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 Gager, C. Stuart (Charles Stuart), 1872-1943. Philadelphia, P. Blakiston's son & co.
Size: 1859px × 1345px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorgag, bookcentury1900, bookdecade1910, booksubjectbotany
