EXTERNAL MORPHOLOGY OF THE STEMS OF CALAMITES. 523 
the stri: being perhaps discontinuous. irregular and wavy. This feature is 
here possibly better seen than in tle former specimen. 
Another fragmentary specimen, possibly also belonging to this species, is 
shown natural size on Pl. 28. fig. 4. This again exhibits part of a branch- 
hearing node and two internodes. The transverse wrinkling of the latter is 
here more prominent than in the other specimens illustrated above. In this 
case the longitudinal striations are extremely taint. 
The transversely elongated form of the leaf scars is here particularly 
prominent. The specific determination of this specimen is, however, 
somewhat doubtful. 
Another specimen, al:o of somewhat doubtful determination but possibly 
C. undulatus, is shown natural size on Pl. 24. fig. 14. Two internodes are 
here seen, the surfaces of which have the same characters as in the specimens 
above described. 
Remarks.—The question whether rovt scars can occur on the internodes of 
Calamite stems is a disputed one. In the specimen figured on PI 24. fig. 15, 
as originally pointed out by Goode, there are scars on the /nternodes, which 
may possibly be interpreted as root scars. Similar specimens have been 
figured by other authors on several occasions, and these scars occur in the 
case of several species and also in Dictyocalamites. Kidston and Jongmans * 
regard these scars as due to some damage to the bark during the life of the 
plant. They add that “the position of these markings precludes the 
possibility of their being root scars.” From this remark we infer that these 
authors only recognise as root scars those which are confined to the nodes. 
We are inclined, however, to regard these internodal scars as marking the 
position of adventitious roots, at any rate in some cases. Their occurrence 
is too common T for them to be explained as mere local imperfections of the 
bark. Until, however, roots are actually found attached, proof of this 
contention must remain lacking. 
Distribution. 
Middle Coal Measures—very rare. 
Pembrokeshire ; Notts, and Derby. 
CALAMOPHLOIOS VERTICILLATUS, Arber. (Plate 24. fig. 18.) 
1835. Calamites verticillatus, Lindley & Hutton, Foss. Flora, vol. ii. pl. 139. 
1886-1888. ? Calamophylutes verticillatus, Zeiller, Flore Foss, Bass. houill. Valenciennes 
p. 360, pl. 57. fig. 2. 
1893. Calumitina verticillata, Kidston, Trans. Roy. Soc. Edin. vol. xxxvii. part 2, p. 311, 
pl. 4. tig. 18. 
1908. Calamitina varians, Renier, Rev. Univ. Mines, etc., series 4, vol. xxi. p. 42, text- 
fig. 17 on p. 42. 
* Kidston & Jongmans (1915) p. 13. 
T Kidston & Jongmans (1915) pl. 55, fig. 2. 
LINN. JOURN,— BOTANY, VOL. XLIV, 
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