MACROSTACHYA 73 



and these cones are among the most striking fossils of 

 the Coal -period. There is great doubt as to the 

 internal structure of the cones. M. Renault examined 

 the carbonised cones of a Macrostachya, found in con- 

 nection with the stem, which was of 

 the Calamitina type (see below, p. 

 74), and showed the usual Cala- 

 mitean structure. The fructification 

 proved to be heterosporous, the 

 microsporangia and megasporangia 

 occurring on the same strobilus, 

 as is the case in C alamo stachys 

 Casheana} 



7. Classification. — Before leaving 

 the Calamarieae I must say a few 

 words as to their classification. This 

 is a most difficult, and indeed in the 

 present state of our knowledge, in- 

 soluble question, because we only 

 have the plants as preserved in the 

 form of fragments. Consequently, 

 we shall not be surprised to find that 



Fig. 32. — Macrostachya. in- 



the classification of Calamarieae has /undn>uii/ormis. Cone 



1 1 . Hi. rr ■ borne laterally on a 



been based on totally different pnn- branch. Hair nat. size. 

 ciples, according to the parts of the After Weiss ' 

 plants selected. For example, Weiss classified Cala- 

 marieae by means of the characters presented by their 

 medullary casts, and more especially according to the 

 form and distribution of the scars marking the position 

 of the branches. For the purposes of geologists his is 



1 Notice sur les Calamarties, Part iii., Autun, 1898. 



