262 



SCIENCE 



[N. S. Vol. XXXIX. No. 998 



dimensions of the pores. As many as six rows may 

 be found where the tracheid touches the ray cell, 

 and here the pores may extend considerably be- 

 yond the border of the pits. Again, in arrange- 

 ment, the pits, though usually alternate, may be 

 opposite, and are often scattered. 



One remarkable feature is that many tracheids 

 have bent ends, usually at the rays. These bent 

 ends reach over several tracheids, and thus afford 

 a means for radial conduction. Such tracheids 

 have long been known in the Araucarineas and are 

 considered to be ancestral to true ray tracheids. 

 They are for the first time described in a Cordai- 

 tean form. 



Trabecule are present in many tracheids; a fea- 

 ture which has not been noted previously among 

 Cordaitean forms. Peculiar wandering parenchy- 

 matous cells are also found associated with the 

 medullary rays. 



Tyloses: A Study of Their Occurrence and Prac- 

 tical Significance in Some American Woods: 



Eloise Gerry. 



In this study of the occurrence of tyloses in 

 wood from trees of commercial size grown in the 

 United States, 203 specimens were examined. The 

 143 specimens of hardwoods include 94 species be- 

 longing to 45 genera, 24 of which contained ty- 

 loses. The 60 specimens of conifers included 45 

 species belonging to 13 genera, 1 of which con- 

 tained tyloses. Of the total 139 species examined, 

 56 belonging to 25 genera^ contained tyloses. 



Tyloses were found in the sapwood of all the 

 species where their presence was established in 

 the heartwood. 



Well-developed tyloses were found in the outer- 

 most rings near the bark of 30 species of hard- 

 woods. 



True tyloses occur in the wood tracheids of cer- 

 tain pines, principally of the white pine group. 



Epithelial cells sometimes effect a partial or 

 even a complete tylose-like closing of the resin 

 canals in Finns, Larix, Picea and Faeudotsuga. 



A considerable proportion of the vertical canals, 

 even in the heartwood of the pines, are wholly or 

 partly open. 



Tyloses act like a natural filler in the hardwoods. 



The woods where tyloses are abundant are, as a 

 rule, durable. 



2 ^sculus, Fagus, Liquidamhar, Liriodendron, 

 Magnolia, Oxydendrum, Platanus, Populus, Salix, 

 Castanea, Catalpa, Celtis, Chilopsis, Eucalyptus, 

 Fraxinus, Hicoria, Juglans, Morus, Quercus, Shus, 

 Boiinia, Sassafras, Toxylon, Ulmus, Finns. 



Tyloses, because they are very impermeable to 

 air, water and creosote, reduc* the penetrance of 

 the woods in which they are strongly developed, 

 thus decreasing, for instance, the tendency for 

 such woods to become water -logged. 



The presence of tyloses closing the vessels of a 

 hardwood does not, however, prevent the pene- 

 trance of a preservative such as creosote into the 

 other wood elements. 



{To be concluded) 



Geoege T. Moore, 



Secretary 



SOCIETIES AND ACADEMIES 



THE TENNESSEE ACADEMY OF SCIENCE 



The annual meeting of the Tennessee Academy 

 of Science was held in Furman Hall, Vanderbilt 

 University, Nashville, Tenn., on November 28, 

 1913. President Watson Selvage delivered an ad- 

 dress relative to the aims and purposes of the Acad- 

 emy, and the following papers were read and dis- 

 cussed: 



"A Natural Bridge of Tennessee in Process of 

 Formation, " by H. D. Miser. 



' ' Physiographic Features of Tennessee, " by L. 

 C. Glenn. 



"Development of the Phosphate Industry in 

 Tennessee," by Lucius P. Brown. 



"Caverns and Eock Shelters of the Cumberland 

 Valley," by W. E. Myer. 



' ' Food Preservation, " by L. C. Bliss. 



"A New Geological Map of Tennessee," by A 

 H. Purdue. 



' ' Some Neglected Principles of Physiography, ' 

 by A. H. Purdue. 



"Some Early Topographic Maps," by L. C, 

 Glenn. 



The following officers were elected for the en 

 suing year: 



President — L. C. Glenn, Vanderbilt University, 

 Nashville. 



Vice-president — W. E. Myer, Carthage. 



Secretary — Roseoe Nunn, 1235 Stahlman Build- 

 ing, Nashville. 



Treasurer — Archibald Belcher, Middle Tennessee 

 Normal School, Murfreesboro. 



Editor — James A. Lyon, Southwestern Presby- 

 terian University, Clarksville. 



The president appointed as members of the exec- 

 utive committee, S. M. Bain, University of Ten- 

 nessee, Knoxville, and E. J. MeCroskey, Lebanon. 



EOSCOE N0NN, 



Secretary 



