The Structure of Mesoxylon multirame 
BY 
D. H. SCOTT, F.R.S. 
With Plates XI-XIV and two Figures in the Text, 
Contents. 
The Type 
The Pith . 
The Leaf-traces 
The Axillary Shoots. 
The Wood and Phloem 
The Cortex 
PAGE 
437 Other Specimens . 
444 Explanation of Plates 
439 Summary 
442 
444 Bibliography 
438 A Possible Fructification 
PAGE 
• 445 
• 45 2 
• 453 
• 455 
. 456 
I N continuation of the description of the Coal Measure genus Mesoxy¬ 
lon (Scott and Maslen, 1910; Maslen, 1911; Scott, 1912) an account 
is given in the present communication of the species M. multirame, one of 
those briefly characterized in the Preliminary Note of 1910. It will be 
remembered that the genus Mesoxylon differs essentially from Cordaites in 
the presence of centripetal wood in the stem. 
The Type, 
Several specimens of the species now to be described, Mesoxylon multi¬ 
rame , are known. In the first instance I propose to deal with the type- 
specimen, on which the short description in the Note by Mr. Maslen and 
myself (1910) was based; this was received from Mr. Lomax in April, 
1907. There are 15 transverse and 6 longitudinal sections (Nos. 2339-2343 
and 2344-2349 in my collection). The transverse series is remarkably good 
for following the course of the leaf-traces and axillary steles ; the latter 
accompany the great majority of the leaf-traces. 1 
The diameter of the stem is about 2-5-27 cm., that of the pith 
about 12-5 mm. The stem is a rather young one, the wood only reaching 
a thickness of about 2*5 mm. and the phloem and pericycle together about 
1 mm. The cortex is from 3 to 3*5 mm. thick. The leaf-traces are 
numerous and succeed one another very rapidly, so that two or three are often 
1 The true order of the transverse sections, from above downwards, follows the numbers with 
two exceptions—2335 comes above 2334 an ^ 2 34 2 above 2341. 
[Annals of Botany, Vol. XXXII, No, CXXVII, July, 1918.] 
