Fossil Botany; Being an Introduction to Palaeophytology from the Standpoint of the Botanist

Fossil Botany; Being an Introduction to Palaeophytology from the Standpoint of the Botanist

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This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1891 edition. Excerpt: ...and each cushion bears a detachment-scar at its most elevated point. This scar answers to the place of separation of a leaf, the whole cushion to the decurrent leaf-base which has remained on the stem. In the crowded position of the cushions which are everywhere in contact with one another the parastichies are very clearly shown, as in fircones, and careful study of them discloses very complicated conditions in the arrangement of the leaves. In the large stem of Lepidodendron Sternbergii preserved in the Museum at Prague, Max Braun found that the phyllotaxy was 5% 2. Elaborate researches into the phyllotaxies which occur in Lepidodendreae have been made by Naumann3 and Stur 4. From these it appears that the complicated succession of many-membered cycles with definite divergences, which are exceptional in fir-cones but are frequent in Lycopodiaceae, are the rule in Lepidodendreae, and that simple f spiral arrangement is seldom observed. The latter was found by Stur 6 in Lepidodendron Haidingeri with the divergence %: two-leaved whorls occur in L. Veltheimianum with the divergence SS, and three-leaved whorls in the same species with the divergence W: five-leaved whorls with the divergence 58395 and seven-leaved whorls with the same divergence were ascertained in Ulodendron commutatum. From Stur's original account we may learn how he overcame the difficulty arising from the circumstance, that the entire circumference of the stem is not usually open to examination. Stur6 has also given an elaborate description of the single cushion in all its details. The lateral angles of its rhombic outline are obtuse and the upper and lower angles are acute, and hence it is seen to be bounded by two lateral sinuous lines. It is separated from the eight...show more

Product details

  • Paperback | 182 pages
  • 189 x 246 x 10mm | 336g
  • Rarebooksclub.com
  • United States
  • English
  • black & white illustrations
  • 1236973577
  • 9781236973573