Access

You are not currently logged in.

Access JSTOR through your library or other institution:

login

Log in through your institution.

If You Use a Screen Reader

This content is available through Read Online (Free) program, which relies on page scans. Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
Journal Article

Fossil Cycadales of Argentina

Analia E. Artabe and Dennis Wm. Stevenson
Botanical Review
Vol. 65, No. 3 (Jul. - Sep., 1999), pp. 219-238
Published by: Springer on behalf of New York Botanical Garden Press
Stable URL: http://www.jstor.org/stable/4354347
Page Count: 20

You can always find the topics here!

Topics: Fossils, Genera, Stems, Epidermal cells, Stomata, Pith, Flora, Plant cells, Guard cells, Taxa
Were these topics helpful?
See somethings inaccurate? Let us know!

Select the topics that are inaccurate.

Cancel
  • Read Online (Free)
  • Subscribe ($19.50)
  • Add to My Lists
  • Cite this Item
Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
Fossil Cycadales of Argentina
Preview not available

Abstract

A survey of Cycadalean taxa of Argentina (including Antarctica) is presented. The record of leaves represented by Nilssonia, Pseudoctenis, Ctenis, Mesodescolea, Ticoa, Almargemia, Kurtziana, and Zamia genera are summarized. Recent investigations made of cuticles with transmission and scanning electron microscopy are included. In stems, a preliminary study of two forms found in the Upper Cretaceous of Río Negro Province are incorporated into Michelilloa, Bororoa, and Menucoa. The fossil record shows some characters of leaf morphology, presence of inverse xylem and medullary bundles, two kinds of leaf traces, and monoxylic and polyxylic steles of systematic importance when compared with both extant and fossil cycads. Affinities of fossil taxa related to extant families are suggested through analysis of the above-mentioned characters. The presence of medullary vascular rings related to the emission of terminal reproductive strobili are recognized in Bororoa and Menucoa. This character associated with polyxyly makes it possible to assign these genera to the Zamiaceae-Encephalartoideae sensu Stevenson, widening the paleogeographical distribution of this subfamily.

Page Thumbnails

  • Thumbnail: Page 
219
    219
  • Thumbnail: Page 
220
    220
  • Thumbnail: Page 
221
    221
  • Thumbnail: Page 
222
    222
  • Thumbnail: Page 
223
    223
  • Thumbnail: Page 
224
    224
  • Thumbnail: Page 
225
    225
  • Thumbnail: Page 
226
    226
  • Thumbnail: Page 
227
    227
  • Thumbnail: Page 
228
    228
  • Thumbnail: Page 
229
    229
  • Thumbnail: Page 
230
    230
  • Thumbnail: Page 
231
    231
  • Thumbnail: Page 
232
    232
  • Thumbnail: Page 
233
    233
  • Thumbnail: Page 
234
    234
  • Thumbnail: Page 
235
    235
  • Thumbnail: Page 
236
    236
  • Thumbnail: Page 
237
    237
  • Thumbnail: Page 
238
    238