. Piante; un libro di testo di botanica. La botanica. Spara. 85. Steli che aumentano di diametro per la maggior parte appartengono a grandi gruppi chiamati dicotiledoni e conifere. Alla prima appartengono la maggior parte dei nostri comuni alberi, come acero, quercia, faggio, hickory, ecc. (Vedi Figg. oS, 59, 60, 01), come pure la grande maggioranza delle erbe comune; per questi ultimi appartengono i pini, hemlocks, ecc. (Vedere figg. 5V,, 57, 192, 193, 194). Questo aumento annuale in diametro consente che la struttura ad albero per mettere fuori un aumentato numero di rami e quindi fogliame esce ogni anno, in modo che la sua capacità di lavoro in foglia essere- proviene una maggiore anno dopo anno. Un

• Collaboratore: The Book Worm / Alamy Foto Stock
• ID dell’immagine: RDWC0C
• Dimensioni dei file: 7,2 MB (168,2 KB Download compresso)
• Liberatorie: Modello - no | Proprietà - no
• Dimensioni: 2118 x 1180 px | 35,9 x 20 cm | 14,1 x 7,9 inches | 150dpi

Altre informazioni

Questa foto è un'immagine di pubblico dominio, il che significa che il copyright è scaduto o che il titolare del copyright ha rinunciato a tale diritto. Alamy addebita un costo per l'accesso alla copia ad alta risoluzione dell'immagine.

Questa immagine potrebbe avere delle imperfezioni perché è storica o di reportage.

. Plants; a text-book of botany. Botany. SHOOTS. 85. Stems which increase in diameter mostly belong to the great groups called Dicotyledons and Conifers. To the former belong most of our common trees, such as maple, oak, beech, hickory, etc. (see Figs. oS, 59, 60, 01), as well as the great majority of common herbs; to the latter belong the pines, hemlocks, etc. (see Figs. 5V, , 57, 192, 193, 194). This annual increase in diameter enables the tree to put out an increased number of branches and hence foliage leaves each year, so that its capacity for leaf work be- comes greater year after year. A reason for this is that the stem is conducting important food sup- plies to the leaves, and if it in- creases in diameter it can conduct more supplies eacl: year and give work to more leaves. 59. Monocotyledons.âIn other stems, however, the vessels are arranged differently in the central region. Instead of forming a hol- low cylinder enclosing a pith, they are scattered through the central region, as may be seen in the cross- section of a corn-stalk (see Fig. SO). Snch stems belong mostly to a great group of plants known as Monocotyledons, to which belong palms, grasses, lilies, etc. For the most part such stems do not increase in diameter, hence there is no branching and no increased foliage from vear to year. A palm well illustrates this habit, with its columnar, unbranching trunk, and its crown of foliage leaves, which are about the same in number from year to year (see Figs. 81, S2). 60. Ferns, âThe same is true of the stems of most fern- plants, as the vessels of the central region are so arranged that there can be no diameter increase, though the ar- ^â^âiâ^ ' 1 â â Fig. 80. A corn-stalk, showing cross-section and longitudinal section. The dots represent the scattered bundles of ves- sels, which in the longitudinal section are seen to he long fiber-like strands.. Please note that these images are extracted from scanned page images that may have been digitally enhan

Parole chiave associate all'immagine

• bookcentury1900
• bookdecade1900
• booksubjectbotany
• bookyear1900