Mazocarpon or the Structural Sigillariostrobus. 
BY 
MARGARET J. BENSON, D.Sc., F.L.S. 
Professor of Botany , Royal Holloway College , Surrey. 
With Plates XVII and XVIII and four Figures in the Text. 
Contents. 
Tart I. Description of Mazocarpon. 
SECTION TAGE 
I. Introduction. 569 
II. The Megasporange.570 
III. The Megaspore. 572 
IV. The Cone.574 
“V. The Sporophyll or Bract.575 
VI. The Microsporange.. ... 577 
VII. Abortive and Semi-abortive Sporangia.578 
VIII. The Problem of Species.578 
IX. Summary of Part I ............ 579 
Part II. Grounds for the Identification of Mazocarpon 
and Sigillariostrobus. 
X. Introduction to Part II.580 
XI. Detailed Comparison with Recorded Incrustation Remains of Sigillariostrobus . .581 
1. The Sporangia ............ 581 
2 The Cones.583 
Part III. General Discussion of Results. 
XII.585 
Part I. Description of Mazocarpon. 
Section I. Introduction . 
S PECIMENS of the megasporangia of this new type have been gradually 
accumulating for a long time. The large megaspores, showing a con¬ 
siderable range of sectional form and for the most part with a portion of 
their sporange-wall adhering to their base, are relatively frequent, especially 
in Shore nodules. Specimens are also in hand from those of Halifax, 
Stalybridge, Dulesgate, Hough Hill, and Bacup. Two broken but well- 
characterized sporangia of another species 1 have been obtained from 
a block of the calciferous sandstone material from Pettycur, Scotland. 
A transverse section of a cone from an unrecorded locality, and probably 
specifically distinct, was most kindly contributed by Prof. Weiss from the 
1 Benson: N. Ph. vii, 1908, p. 143, Figs. 25 and 26. 
[Annals of Botany, Vol. XXXII. No. CXXVIII. October, igj8.] 
