1914] GROOM—TRACHEID-CALIBER 307 
LITERATURE CITED 
1. Groom, Percy, Remarks on the oecology of Coniferae. Ann. Botany 24: 
241-269. IQIo. 
2 , and Rusuton, W., The structure of the wood of East Indian 
species of Pinus. Jour. Linn. Soc. London Bot. 41:457-490. 1913. 
- Mayr, H., Die Waldungen von Nord-Amerika. 1890. 
. PENHALLOW, D. T., A manual of the North American Gymnosperms. 1907. 
5. SARGENT, C. S., Manual of the trees of North America. London. 1905. 
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