. Text-book of botany, morphological and physiological. Botany. FORMS AND SYSTEMS OF TISSUES. 87 Papayacex (Carica and Vasco7icelld) the Iaticiferous vessels, on the other hand, run through the xylem-portion of the fibro-vascular bundles; they— the cells by the coalescence of which they are formed—are repeatedly produced in layers from the cambium with the other elements of the xylem; pitted and reticulately thickened vessels alternate with them. The branches of the Iaticiferous vessels envelope these in all directions, and are sometimes firmly fixed to them superficially; but hori- zontal
. Text-book of botany, morphological and physiological. Botany. FORMS AND SYSTEMS OF TISSUES. 87 Papayacex (Carica and Vasco7icelld) the Iaticiferous vessels, on the other hand, run through the xylem-portion of the fibro-vascular bundles; they— the cells by the coalescence of which they are formed—are repeatedly produced in layers from the cambium with the other elements of the xylem; pitted and reticulately thickened vessels alternate with them. The branches of the Iaticiferous vessels envelope these in all directions, and are sometimes firmly fixed to them superficially; but hori- zontal branches of these tubes also penetrate the medullary rays, and terminate, towards the primary cortex, in scat- tered ramifications or recurrent knots, as also in the pith if the stem is hollow. As in the other families, a copious anastomosis of Iaticiferous vessels is de- veloped in the horizontal partition-walls which the medullary tissue forms at the origin of each petiole in the hollow of the stem, penetrating the horizontal partition-wall in countless ramifications and in several layers one over anothe r, and connecting the vessels belonging to the medullary rays with these of the whole wood-cylinder. In Papaveraceae (Chelidonium, Papaver, Sanguinaria) the Iaticiferous vessels are also very per- fectly developed; they are not here, however, as in the families just named, united into ribbon-shaped groups, but run mostly at a greater distance from one another, dispersed through the phloem and the surrounding paren- chyma; single ones appear also in the pith, but do not penetrate into the xylem. Lateral outgrowths and cross- anastomoses are seldom found in the stem, but abundantly in the leaves, and especially in the carpels, in which close- meshed reticulations are formed, ac- cording to linger, in the parenchyma- tous fundamental tissue; similarly also in the cortex of the root. In this family, especially in the parenchyma of the root of Sanguinaria canadensis, the orig
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectbotany, bookyear1882
