HOLDEX. — CRETACEOUS PITYOXYLA. 617 



impossible to tell, owing to imperfect preservation), the rays are 

 devoid of tracheides, and hear out the conclusion of Jeffrey (11) that 

 the nuijority of pines of this horizon had not yet ac([viired them. The 

 afHnities of this specimen nmst, therefore, lie with one of the four 

 Abietineous genera normally possessing resin canals, — Pinm, Picea, 

 Larix and Pseudoisuga. Both the last two have well marked wood 

 parenchyma at the end of the year's growth. Since this feature is 

 lacking in our fossil, it cannot be related to them. Between P'nius and 

 Picea, there is little occasion for hesitation. The abundant, tylosed 

 resin canals, complete absence of spiral thickenings, thin-walled 

 parenchyma forming the epithelium of the canals and the cells of the 

 medullarv ravs, clearlv indicate its connection with Pinus. Another 

 criterion for distinguishing the wood of Pinus and Picea is the woimd 

 reaction. As pointed out by Jeffrey (1) dense tangential series of resin 

 canals are an invariable concomitant of injury in the case of Picea. 

 One fragment of the lignite under consideration had a large wound 

 cap. This was carefully examined, but no trace of traumatic canals 

 found. That the capacity for such a reversion had been acc[uired as 

 early as the Cretaceous, is proved by the presence of a traumatic series 

 in Pinitcs Ruffordi (12) from the Wealden of England. If our fossil 

 were related to Picea, as severe a wound as it had received would have 

 unquestionably stimulated this characteristic reaction. Against this 

 proposed affiliation with Piiuis, may be brought forward the absence 

 of short shoots. Fontaine (8) however, has described from the Po- 

 tomac certain coniferous remains with both fascicular leaves on lat- 

 eral and terminal short shoots, and also primary leaves, borne directly 

 on the main axis, which are spirally arranged like those of seedling 

 pines. In view of the small amount of available material, it is en- 

 tirely possible that our specimen really possessed typical short shoot 

 organs. Jeffrey (9) has suggested that Prepinus may belong with this 

 Lepiostrobus of Fontaine's. If such is the case, the lignite under 

 discussion may be referred to Prepinus. Its characteristics are, in- 

 deed, extremely like those of the wood of the brachyblast of P. state- 

 nensis. Both have sclerified nests in the pith, resin canals in two 

 planes, highly resinous rays with piciform lateral pitting and tan- 

 gential pitting of the tracheides. On the other hand, there are certain 

 important differences. Modern pines may be divided into the two 

 classes, — hard and soft. Disregarding the differences in ray trache- 

 ides, the characteristics of the two are, — first, hard pines have a 

 double, soft, — a single, leaf trace (in both, however the trace leaves 

 the wood of the brachyblast as one and divides in the cortex) ; second, 



