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MAZOCARPON OEDIPTERNUM 



COMPARISON OF M. OEDIPTER- 

 NUM WITH OTHER SPECIES 

 OF MAZOCARPON 



Mazocarpon petty cur ense Benson 

 (1918). — This species from the Lower 

 Carboniferous Calciferons Sandstone is 

 geolog:ically the oldest species known. 

 Information in regard to it is scant 

 (Benson 1908; 1918, p. 578; and Scott, 

 1920, p. 216). The only illustrations are 

 the drawing's given by Miss Benson in 

 connection with her discussion of the 

 sporangiophore (New Phjrt. fig. 25, 

 1908). The chief distinction upon which 

 this species is based is that the apiculate 

 megaspores are more numerous than in 

 M. shorense and other species. From 

 Miss Benson's figures it may also be 

 inferred that the definite arrangement 

 of megaspores in the sporangium and 

 the spore form characteristic of the 

 Pennsylvanian species, had not yet been 

 established when the Calciferous Sand- 

 stone sediments were deposited. A large 

 amount of intrasporangial tissue is defi- 

 nitely shown for both megasporangia 

 and microsporangia of M. pettycurense. 

 The megasporangium apparently lacks 

 lateral keels, and this also may be an 

 identifying characteristic. 



Miss Benson notes later (1918, foot- 

 note, p. 579) that the microsporangium 

 of M. pettycurense (1908, fig. 25b) is 

 magnified 30 times, whereas the mega- 

 sporangium (fig. 25a, 1908) is magni- 

 fied 39 times, but the two are drawn 

 as if they were the same size. This is 

 a difference in actual linear dimensions 

 of about 23 per cent, the microsporan- 

 gium being the larger. Whether this is 

 an actual size difference or whether the 

 sections were merely from different tan- 

 gential positions on the cone cannot be 

 judged. 



Mazocarpon cashii (slide 472 A, Man- 

 chester Collections).— This species is 

 probably of Lower Coal Measures (up- 

 per Lanarkian) age, although the source 

 of the type specimen is not definitely 

 known. It is said to be distinguished 

 from Mazocarpon shorense by the sporo- 

 phyll traces in the cone axis which ' ' are 

 surrounded by a sheath as they pass 

 out through the lacunar middle cortex" 

 and by transfusion tissue at the base 



of the megasporangium which is "more 

 highly differentiated". Miss Benson's 

 illustrations of Mazocarpon cashii (her 

 figs. 15, 16, and 17) also seem to indi- 

 cate a form somewhat smaller than 

 Mazocarpon shorense. However, Mazo- 

 carpon cashii is not well enough charac- 

 terized at present to offer any adequate 

 basis for comparison with M. oedipter- 

 num beyond that presented with regard 

 to Mazocarpon shorense which, in any 

 event, is very closely related to it. 



Mazocarpon shorense. — This species is 

 much better known than either of the 

 other English species, since it is the 

 form chiefly dealt with in Miss Benson's 

 paper of 1918. It was obtained from the 

 Great Coal-ball horizon- (Halifax Hard 

 Bed) and from the Hough Hill and 

 Stalybridge coal which is slightly older. 

 It also has been recorded comparatively 

 from the Finefrau-Nebenbank coal in 

 Limberg, Holland, by Koopmans (1928, 

 p. 21). It thus appears to be a fairly 

 common and widespread form which, 

 as far as is known, is restricted to the 

 lower Westphalian A. A detailed de- 

 scription of M. shorense has been pre- 

 pared, summarized from Miss Benson's 

 account (1918) and given below, in 

 order that a close , comparison can be 

 made with M. oedipternum previously 

 described. Where measurements were 

 not originally provided by Miss Benson, 

 they have been obtained as far as possi- 

 ble by measurement from the published 

 illustrations. Attention is called to a 

 few discrepancies and to points where 

 additional information would be helpful. 



Cones pedunculate, 13.5 mm. in diameter, 

 more than 8 cm. long. It is not definitely- 

 known whether or not cones were unisexual, 

 Sporophylls are characteristically deciduous 

 in their entirety; arrangement on the cone 

 axis is stated to be in a "close spiral" but 

 the arrangement also may have been verti- 

 cillate. Cone peduncle and axis somewhat 

 hexagonal, about 3 mm. in diameter, outer 

 sclerotic tissue relatively thick (slightly 

 under a millimeter). Mesarch sporophyll 

 traces and associated tissues pass through 

 sclerotic tissue on a rather long slant. Stele 

 apparently medullated, about % mm. in di- 

 ameter, with projecting protoxylem points; 

 other details unknown. Sporophyll pedicels 

 diminish in width to about 1 mm. at their 

 point of attachment to the cone axis. Pedi- 

 cel extends radially for about 5 mm. and 



