3, the plant remains are more heavily carbonized than 
appears to be possible for a member of the family Char- 
aceae and probably for any alga. 
Until more sphenopsids are discovered in Lower De¬ 
vonian or Upper Silurian rocks, the forms most closely 
related to Sphondylophyton can be inferred only from 
megascopic characteristics. It may be said, however, 
that Sphondylophyton hyenioides is best interpreted as an 
early member of the Sphenopsida. 
As the specific name of the plant implies, Sphondy¬ 
lophyton bears a striking resemblance to Hyenia spheno- 
phylloides Nathorst (7,12) and to Hyenia elegans Krausel 
& Weyland (9,10) of the Middle Devonian, hitherto the 
earliest known undoubted sphenopsids. The general tuft¬ 
ed habit of the plant and the verticillation of the foliar 
organs correspond rather closely with that of the two 
species of Hyenia. There are, however, marked differ¬ 
ences : Sphondylophyton has no longitudinal striations on 
the axes, has foliar organs once (basally) instead of twice 
dichotomous as in Hyenia , and has, in general, a more 
thalloid habit than Hyenia. Sphondylophyton is much 
more alga-like in appearance than Hyenia. For these 
reasons, and because of the lack of fertile material, the 
Wyoming sphenopsid deserves generic rank. 
Climaciophyton trifoliatum Steinmann & Elberskirch 
(11,14) is a sphenopsid of the Lower Devonian of Ger¬ 
many. Until the discovery of Sphondylophyton , Clima¬ 
ciophyton was the only known Lower Devonian plant of 
possible articulate affinity. It is curious, however, that 
beyond the verticillation, Climaciophyton bears no close 
resemblance to Sphondylophyton , and it is probable that 
the relationship between the two forms is distant. T e 
leaf-like appendages of Climaciophyton are more or less 
obtusely triangular with a number of nerves. Moreover, 
Sphondylophyton is a much larger plant than Climacio- 
[29 ] 
