1897] BOTANICAL SOCIETY OF AMERICA 183 
details of the process were given for selected genera, Dianthus, 
Portulaca, Allionia, Phytolacca, Polygonum, and Rumex. The 
author’s résumé is as follows: Three types of transition may 
be distinguished with respect to the constitution of the bundle 
trace of the cotyledons; holostelar, where the trace is composed 
of the entire vascular system of the hypocotyledonary stele ; 
prototracheidal, when the prototracheids are the xylem elements 
to pass into the cotyledons; metatracheidal, when the cotyledon- 
ary trace is formed by the metatracheids. With reference to 
the perfection of the transition in the hypocotyl, the transition 
may be truncate, or complete. In the first case, the xylem 
and phloem reach the cotyledons in centripetal, or secantial 
orientation ; in the second, the orientation is centrifugal, and the 
stele becomes collateral. 
D. P. Pennattow: A revision of the species of Picea occur- 
ring in northeastern America. 25 min. 
The author reviewed the relations of the spruces of north- 
eastern America with special reference to the possible separation 
of the red spruce as a distinct species. In 1887 the late Dr. 
George Lawson advocated the separation of the red from the 
black spruce with which it has been merged for the last seventy 
years, or since the time of Pursh. A critical study of authentic 
material, both in the field and in, the laboratory, leads to the 
conclusion that the red spruce possesses well defined specific 
characters which separate it from all others. This evidence is 
derived primarily from the cones and leaves, but is supported 
by data derived from the internal structure of the stem. It is 
also highly probable that there may be another, and hereto- 
fore unrecognized variety or species of spruce closely allied to 
the black spruce, but further study in this direction is needed 
The author also recognizes a well defined variety of the 
white spruce, locally known as the cat or skunk spruce, for 
which he proposes the name fetida in allusion to its character- 
istic odor, 
Epwarp Ler Greene: Bibliographic difficulties. 30 min. 
The author cited numerous instances of the complexity of 
