xylem Bot.
(ˈzaɪlɛm)
[mod. (Nägeli in Ger.) f. Gr. ξύλον wood: cf. phloem.]
Collective name for the cells, vessels, and fibres forming the harder portion of the fibrovascular tissue; the wood, as a tissue of the plant-body. Also attrib.
| 1875 Bennett & Dyer tr. Sachs' Bot. 94 The different forms of tissue of a differentiated fibro-vascular bundle may be classified into two groups, which Nägeli calls the Phloëm- (Bast) and Xylem- (Wood) portion of the bundle... The xylem-portion of the fibro-vascular bundle has mostly a strong tendency to thicken its cell-forms. Ibid. 95 These horizontal elements..may be..designated as rays; within the xylem they are called xylem-rays, within the phloëm, phloëm-rays. 1894 D. H. Scott Struct. Bot. i. Flowering Pl. 56 The woody character of the cell-walls of the xylem is due to the presence of a substance called lignine. |