. Studies in fossil botany . Paleobotany. HETERANGIUM 405 recognised, and as all subsequent research has confirmed, the evidence of consanguinity is clear and convincing. The primary wood in Heterangium is composed throughout of irregular anastomosing groups of tracheae, interspersed with strands of conjunctive parenchyma. Fig. 156.—Heterangium Grievii. Part of transverse section, from outer part of stele, showing a primary xylem-strand and adjacent tissues, px, protoxylem of strand ; -*-, centripetal, jr1, centrifugal, primary wood ; nix, metaxylem, , conjunctive parenchyma; .r2, secondary
. Studies in fossil botany . Paleobotany. HETERANGIUM 405 recognised, and as all subsequent research has confirmed, the evidence of consanguinity is clear and convincing. The primary wood in Heterangium is composed throughout of irregular anastomosing groups of tracheae, interspersed with strands of conjunctive parenchyma. Fig. 156.—Heterangium Grievii. Part of transverse section, from outer part of stele, showing a primary xylem-strand and adjacent tissues, px, protoxylem of strand ; -*-, centripetal, jr1, centrifugal, primary wood ; nix, metaxylem, , conjunctive parenchyma; .r2, secondary wood; cb, cambium; pit1-, phloem. X 135. Phil. Trans., W. and S. Will. Coll. 1293. (Figs. 154 and 155, x). As a rule, the tracheae are more abundant than the parenchyma, and even where the reverse is the case, there is never any aggregation of the cellular tissue to form a pith. The structure of the primary wood is not, however, uniform in all its parts. Around its periphery, definite clusters. of tracheides can be distinguished, each of which agrees. 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 Scott, Dukinfield Henry, 1854-1934. London, A. and C. Black
Size: 1469px × 1700px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, bookpublisherlondonaandcblack
