50 



PALEOZOIC FOSSIL SPORES 



endosporal membrane may be present, 

 oftentimes shrunken away from the ex- 

 osporal coat. 



.■J^';//Vy-— Hartung's (1933) investiga- 

 tion of spores in fructifications that were 

 referred to six different genera allied with 

 the calamarians has provided an excellent 

 basis for systematic treatment of plants 

 of this sort which are only represented by 

 their isolated spores. In general, the 

 spores do not appear to lend themselves 

 to grouping into restricted generic alli- 

 ances but show a rather generalized char- 

 acter. Certain species may easily be 

 distinguished by spore differences but 

 generic characteristics (in terms of the 

 fructifications) are not present or at least 

 not yet recognized. The genus Calamos- 

 pora therefore must be regarded as co- 

 ordinate with a large proportion of the 

 calamarians as they are now reported. 

 In addition, Nemejc has shown that 

 spores isolated from Noeggerathiostro- 

 bus (Nemejc, 1935) and from Discinites 

 (ibid., 1937) are similar in character and 

 he regards this as sound evidence of alli- 

 ance between these and the articulate 

 groups although the degree of relation- 

 ship is still difficult to evaluate. 



For the present Calamospora is re- 

 garded as allied to the groups just men- 

 tioned and probably is also correlative 

 with some Mesozoic equisetaleans fcf. 

 remarks on Equisetosporiies, p. 47). Thus 

 it is one of the most broadly related of 

 the groups regarded as showing evidence 

 of actual natural relationship. There is 

 no question but that it would be advan- 

 tageous to subdivide the group into sec- 

 tions or into several genera but such a 

 treatment does not seem practicable now. 



Zerndt (1934) has obtained spores of 

 generally similar character by maceration 

 of coal and refers those over 200 microns 

 in diameter to his Type 2. Several dis- 

 tinct species of Calamospora are repre- 

 sented by it. He regards these forms as 

 pertaining to the Calamite group; how- 

 ever, there appears to be no very definite 

 evidence of their generic correlation. 

 Their character nevertheless is indicative 

 of affinity with the calamarian branch of 

 the Articulateae. Many of the type Bg 

 spores of Raistrick (1933, 1934, etc.) are 



referable to this genus but probably not 

 all of them should be classed here. There 

 are a few forms of Punctati-sporites that 

 are very similar in definable features but 

 nevertheless show differences of habit 

 that set them apart from Calamospora. 

 Some of the B3 types Raistrick has illus- 

 trated have trilete rays more extended 

 than they generally are in spores of Cala- 

 mospora, and it is possible that some cala- 

 mosporan forms may have been included 

 in his type Bg. Miss Knox (1938, p. 

 461) has remarked on the affinity the Bg 

 spores and compared them with spores 

 of Calamostachys binneana and Cheiro- 

 sfrobus petty cur ensis. 



Remarks. — Calamospora is unique 

 among genera typically represented by 

 plant spores in that megaspores, micro- 

 spores, and probably isospores, are in- 

 cluded in it. The Calamarians seem not 

 to have developed as specialized a type 

 of heterospory as quickly as the lyco- 

 pods or other groups, and it has been 

 generally doubted that they ever achieved 

 a comparable state of heterosporous de- 

 velopment. Elias believes, however, that 

 seed-like bodies were developed in the 

 group of Annularia stellata and he has 

 distinguished these forms as Carpannu- 

 laria (Elias, 1931). This material was 

 obtained from beds of lower Des Moines 

 age. Such a view also was expressed by 

 Renault and others of the French school 

 when calamites with secondary wood were 

 regarded as gymnosperms, but at least a 

 very large part of the seed evidence then 

 was based on chance association with 

 seeds that we now know have no calamite 

 relationship. No seed megaspores have 

 yet been reported in the bulbose bodies 

 of Carpannularia and this or some simi- 

 lar type of evidence will probably be nec- 

 essary before their seed-like nature can 

 be regarded as established. 



One feature stands out in the sporoge- 

 nous sequence of the calamite alliance. 

 More evidences of incipient heterospory 

 are observable there than in any other 

 fossil group. Apparently normal spores 

 of two sizes but otherwise similar in ap- 

 pearance are found in adjacent sporangia. 

 The larger spores frequently are admixed 

 with abortive forms in various stages of 

 development. Sporangial masses com- 



