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Page:Popular Science Monthly Volume 32.djvu/813

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THE EARLIEST PLANTS.

for which I now prefer the name Nematophyton. When in London, in 1870, I obtained permission to examine certain specimens of spore-cases or seeds from the Upper Ludlow (Silurian) formation of England, and which had been described by Sir Joseph Hooker under the name Pachytheca. In the same slabs with these I found fragments of

PSM V32 D813 Vertical section of a Nematophyton logani.jpg
Fig. 2.Nematophyon Logani (magnified). Vertical section.

fossil wood identical with those of the Gaspé plant. Still later I recognized similar fragments associated also with Pachytheca in the Silurian of Cape Bon Ami, New Brunswick. Lastly, Dr. Hicks has discovered similar wood, and also similar fruits, in the Denbighshire grits, at the base of the Silurian.[1]

PSM V32 D809 Horizontal section of a nematophyton logani.jpg
Fig. 3.Nematophyton Logani (magnified). Horizontal section, showing; part of one of the radial spaces, with tubes passing into it.

They are trees of large size, with a coaly bark and large spreading roots, having the surface of the stem smooth or irregularly ribbed, but with a nodose or jointed appearance. Internally, they show a tissue of long, cylindrical tubes, traversed by a complex network of horizontal tubes thinner walled and of smaller size. The tubes are ar-

  1. "Journal of the Geological Society," August, 1881.