THE FOSSIL FLORA OF THE YORKSHIRE COAL FIELD. 53 



PL II. fig. 11. 



Two of the macrospores magnified 10 times.* These vary in size from 1'5 mm. to 

 2 mm. Their upper surface is covered with short, blunt apiculi, and their lower sur- 

 face bears a triradiate ridge, around which the spore is generally smooth. This 

 triradiate ridge is formed by the mutual pressure of the other three spores, which were 

 developed within the same mother cell, and the smooth parts between the arms of the 

 triradiate ridges represent the points where the macrospores were in contact with each 

 other. I have specimens of somewhat similar macrospores from another source, still 

 united in groups of four.t 



Affinities of Species. 



Sigillariostrobus rhombibractiatus, in the form of bracts, shows a slight approach to 

 Sigillariostrobus Tieghemi, Zeiller,^ but is easily separated from the latter species by its 

 much more truly rhomboidal bracts, with ciliate margin and the apiculate macrospores. 



The pedicel of Sigillariostrobus rhombibractiatus is also destitute of ribs, but is 

 finely apiculate, with minute thorn-like points. In addition to these differences, 

 Zeiller's cone is larger and more robust than our species. 



Middle Coal Measures. 



Locality. — Monckton Main Colliery, near Barnsley, Yorkshire. 

 Horizon. — Barnsley Thick Coal. (W. Hemingway.) 



Sigillariostrobus ciliatus, Kidston, n. sp. 



PI. II. figs. 2-9. 



Description. — Cone cylindrical, pedicellate. Bracts spirally placed on the ligneous 

 axis, linear-lanceolate acute with expanded rhomboidal base, single nerved, margins 

 thickly beset with short, stout cilia. Sporangia walls formed by the hollow basal portion 

 of the bract. Macrospores large, about 1*5 mm. in diameter, apiculate, with triradiate 

 ridge on under surface. Peduncle indistinctly ribbed, and roughened with very small 

 thorn-like apiculi. 



Remarks. — Of this cone I have seen a less number of specimens from Yorkshire than 

 of Sigillariostrobus rhombibractiatus, but a single bract from the Forest of Wyre has 



* These macrospores have a great similarity to those figured in the Proc. Boy. Phys. Soc, vol. ix. p. 109, pi. iii. 

 fig. 7 (Triletes vii.), but it is improbable that they belong to the same species, as macrospores of different species have 

 evidently a great similarity in form and structure, as seen in the case of those belonging to the two cones described in 

 this paper. 



t Binney and Kidston, Proc. Roy. Phys. Soc, vol. ix. p. 113, pi. v. figs. I6d and 16e, 1887. 



X Zeili-,eh, Ann. d. Scienc. Nat., 6". ser., "Bot.," vol. xix. pp. 263 and 266, pi. xi. figs. 1 and 4, 1884 ; also Flore 

 foss. Bassin honil. d. Valenciennes, p. 593, pi. lxxxix. figs. 2-3, 1886 and 1888. 



