The internal structure of fossil vegetables found in the carboniferous and oolitic deposits of Great Britain. Described and illustrated / By Henry T.M. Witham.

  • Witham, Henry T. M. (Henry Thornton Maire)
Date:
1833
Catalogue details

Licence: Public Domain Mark

Credit: The internal structure of fossil vegetables found in the carboniferous and oolitic deposits of Great Britain. Described and illustrated / By Henry T.M. Witham. Source: Wellcome Collection.

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    tudiiial circular or hexagonal apertures. In general, the number of these series seems to he three, sometimes two, and in other instances four or five. Indications of medullary rays occur in these sections, although there hap- pened to be none in the portion figured. Fig. 2. Is a small portion of a slice cut longitudinally parallel to the hark. Viewed in this direction, the texture is equally confused, the elon- gated cellules being much distorted. Their walls seem, however, to he continuous, and entirely destitute of markings. A portion of the trans- verse section of a medullary ray is seen, presenting three irregular rows of cellules. The great fossil tree found in the same quarry in 1830, retains its structure in a more perfect state, although it also is much disorganized. Two sections of it are represented in Plate VII. Fig. 3. Is a section similar to Fig. 2, that is, longitudinal and parallel to the bark. The elongated cellules of the woody tissue are distinctly seen, together with two medullary rays, one of which has two, the other three series of cellules. Sometimes, however, four series are observed. Fig. 4. Represents a longitudinal section, parallel to the medullary rays, and exhibits the elongated cellules in a perfect state of preservation. These cellules are seen covered with series of hexagonal apertures, generally three or two in number, sometimes four. The transverse lines are indica- tions of a medullary ray. There is nothing in the appearance of the sections of these two great trunks of 1826 and 1830, to indicate that they may be of different species ; but it is distinctly seen that they are not Coniferae, or at least not in all respects similar to the Coniferae of the present day. In their transverse sections, the tissue is precisely similar to that of the recent Coniferae, as represented in Plates I. and II., in respect to the elon- o-ated cellvdes or woody fibres, and the medullary rays ; but no decided ap- pearances of concentric circles have been observed. In the longitudinal sec- tions, the two walls of the cells facing the medullary rays, are covered with longitudinal series of hexagonal markings, while the walls next to the me- dullary rays are destitute of markings, being apparently continuous.