DO THE ABIETINEAE EXTEND TO THE 
CARBONIFEROUS? 
ROBERT Boyp THOMSON AND ARTHUR EVERETT ALLIN 
(WITH PLATE XXVI AND TWO FIGURES) 
Jerrrey and CurystLeR, in arecent monograph on the Pityoxyla 
of the Cretaceous (4), assign much importance to the presence of 
Pityoxylon Chasense in the Permian and to the supposed occurrence 
of P. Conwentzianum in the Carboniferous, as indicating the great 
geological age of the Abietineae. They state (p. 13): 
The Pityoxylon Conwentzianum of GOEPPERT from the Carboniferous of 
Waldenburg, which has often been called in question, has received full con- 
firmation from the description of a similar type of Pityoxylon, P. Chasense, by 
PENHALLOW, from the Permian of Kansas. In these two species vertical resin 
canals are said to be absent, although the horizontal canals of the fusiform rays 
are clearly present. There is, accordingly, every reason to believe that the 
Abietineae are a very ancient group in their first appearance. In fact, they 
may be traced geologically quite as far back as the Araucarineae, which it is 
customary at the present time to regard as the oldest of the Coniferales. 
More recently GorHAN (2) has again “called in question” the 
authenticity of P. Conwentzianum as a Carboniferous form. He 
shows that this species whose horizon was never determined cannot, 
on structural grounds, belong to the Carboniferous. In this regard 
he refers (1) to the modern character of the radial pitting of the 
tracheids, which he has shown (1) is entirely lacking in all true 
Carboniferous woods; and (2) to the typical annual rings which 
are present, which are not found in any Carboniferous form. He 
also refers to the doubt expressed by Count Sotms as to the validity 
of P. Conwentzianum, and to the fact that no more material of it can 
be found in the Carboniferous of Waldenburg, from which much 
wood is known. Finally, he again emphasizes the uncertainty as 
to the source and horizon of the material, which he states was found 
“auf eine Halde (!) des Waldenburgischen”’ (2, p. 22). Noreliance 
can thus be placed on this form as indicating the presence of the 
Abietineae in the Carboniferous. 
P. Chasense was described by the late Professor D. P. PEN- 
HALLOw in 1900 from material which was collected by C. S. PROSSER 
339] [Botanical Gazette, vol. 53 
