KIDSTOX: THK FLOKA OF TIIK CAIIHON'IFEIIOUS PERIOD. 199 



A specimen in the British ^luseum shows that the cones 

 of Equisetites llemingwayi were apparently sessile and borne at 

 the nodes of a very Equisetum-like stem. 



MM. llenault and Zeiller have descriy)ed from the Comentry 

 Coal Field an Equisetaceous stem, with distinct sheaths, under 

 the name of E. Moni/i. Some other small specimens from 

 the Carboniferous have been ascribed to Equisetites, but their 

 reference is in manv cases doubtful. 

 Calamites Suckow. 



The Calamites form one of the most prominent types of 

 vegetation in Coal Measure times. True Calamites tlo occur in 

 Lower Carboniferous rocks, that is, below the Millstone Grit, 

 but there tliey take a very unimportant place and are of very 

 rare occurrence. It is onl}^ when we roach tlie Upper Carbon- 

 iferous that they attain their importance, both in numbers and 

 diversity of form. Calamites reached to arborescent dimensions. 



When dealing with the Calamites, we are under the necessity 

 of placing the stems, foliage, and fructification of the plants 

 comprised in this group in separate genera, as in few cases 

 can the foliage and fruit he referred to the parent plant. In 

 fact, even in the genus Calainites in which the stems are placed, 

 there are almost certainly included plants which belong to 

 different genera. One is led to infer this from the structure 

 of Calamitic cones which show among themselves important 

 structural differences. This fact must not be lost sight of, and 

 the genus Calamites should be I'egarded more in the light of 

 a group than of a true genus, but for practical purposes 

 some system of classification, even if pro\isional, must be 

 adopted. 



The late Professor "Weiss divided Calamites into three 

 groups : — 



I. — Calamitina. In Calamitina the branches are borne in 

 verticils, but between each verticil there is one or more nodes 

 from which no branches are developed. 



II. — EucALAMiTES. The stems placed in this group bear 

 branches from every node. 



