. Fossil plants : for students of botany and geology . Paleobotany. xxxvi] VECTIA 419 Vectia. Stopes. Genus incertae Vectia luccombensis Stopes. The generic name Vectia has been given by Dr Stopes^ to some petrified secondary phloem discovered by her at Luccomb Chine in the Isle of Wight: the fossil is from Aptian beds. The mass of phloem is 26 mm. in breadth and consists of regularly alternating bands of thin-walled sieve-tubes and very thick fibres associated with a little parenchyma (fig. 540). To the naked eye the specimen presents an appearance suggestive of rings of growth but this is du
. Fossil plants : for students of botany and geology . Paleobotany. xxxvi] VECTIA 419 Vectia. Stopes. Genus incertae Vectia luccombensis Stopes. The generic name Vectia has been given by Dr Stopes^ to some petrified secondary phloem discovered by her at Luccomb Chine in the Isle of Wight: the fossil is from Aptian beds. The mass of phloem is 26 mm. in breadth and consists of regularly alternating bands of thin-walled sieve-tubes and very thick fibres associated with a little parenchyma (fig. 540). To the naked eye the specimen presents an appearance suggestive of rings of growth but this is due to the presence of bands of 2—3 narrow cells which are probably. Fia. 540. Vectia luccombensis. Transverse section showing the alternation of fibres, s^, s", and radial pairs of pitted elements, v^ and v^; m, meduUary-ray cells; a, parenchyma cell between four thin-walled elements; sp, pits between adjacent fibres; I, much reduced lumen of fibre. (After Stopes.) cork. The whole is penetrated by uniseriate medullary rays. A striking feature is the regular alternation of single rows of fibres with two bands of sieve-tubes; in places the two bands of sieve-tubes are separated by 2—4 rows of very flat, presumably, cork-cells, and similar bands may be adjacent to or pass obliquely across the fibres. The elongated elements described as sieve- tubes, though thin in comparison with the fibres, have thickened walls and on their radial faces are single rows of circular pits, often in pairs; these are almost certainly sieve-areas which have 1 Stopes (15) p. 247, Pis. xxm.—xxv., text-figs. 72—75. 27—2. 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 Seward, A. C. (Albert Charles), 1863-1941. Cambridge : University Press
Size: 1814px × 1378px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1890, bookpublishercambr, bookyear1898
