. South African botany. Botany. THE ROOT OF THE ANGIOSPERM 35 formed kind of cellulose known as lignin. The cross walls have disappeared, and so these cells form long tubes known as vessels stretching throughout the root and stem. The largest cells of the phloem, on the other hand, are still lined with protoplasm, and the cross walls instead of disappearing have become thickened and perforated. Fig. 20.—Transverse Section of the Boot of the Bean. pi. Piliferous layer, c. Cortex, end. Endodermis. pc. Perioyole. X. Xylem. phi. Phloem, p. Pith. (From Darwin's " Elements of Botany ".) hk
. South African botany. Botany. THE ROOT OF THE ANGIOSPERM 35 formed kind of cellulose known as lignin. The cross walls have disappeared, and so these cells form long tubes known as vessels stretching throughout the root and stem. The largest cells of the phloem, on the other hand, are still lined with protoplasm, and the cross walls instead of disappearing have become thickened and perforated. Fig. 20.—Transverse Section of the Boot of the Bean. pi. Piliferous layer, c. Cortex, end. Endodermis. pc. Perioyole. X. Xylem. phi. Phloem, p. Pith. (From Darwin's " Elements of Botany ".) hke sieves. The walls have undergone no change and still give the characteristic reactions of cellulose. These groups of phloem and xylem are arranged around a compact tissue known as the pith, composed of cells very similar to those of the cortex. They are separ- ated from each other by parenchymatous tissue known as conjunctive tissue. The first-formed elements of the xylem known as the protoxylem are towards the 3*. 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 Storey, Francis W; Wright, K. London, New York, Longmans, Green
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectbotany, bookyear1922
