BOTANICAL SYMPOSIUM. 
51 
claimed by some of its wonderful forces of ice and water and 
devastated to a dangerous degree even for persons afoot. 
It is a very good botanical region and the low stage of the river 
at this time permitted easy access to the large wooded rocky 
islands very numerous at this point. 
In the evening Dr. Britton was again elected to the chair and 
the following notes were announced. 
Dr. Britton spoke on Betula Allegheniensis, a recently described 
but well marked species associated with B. lenta and B. nigra 
along the river and hillside ravines. 
In observing these birches particular reason was shown for 
frequent field work. These three species were often growing 
either side by side or within easy eye range of each other and 
their specific characteristics of growth and general outline, color 
and condition of bark, of trunk and twig, leaf shape and shade 
of green were all so evident to the eye in these living examples, 
yet more or less difficult of recognition from descriptive com¬ 
parisons in handbooks or herbaria. Dr. Britton showed also 
other specific variations in the hackberries, two of which were 
recognized as Celtis canina and C . crassifolia. 
Dr. Valery Havard spoke of the persistence of Solidago Purshii 
on the shore rocks, notwithstanding the late terrific devastation 
by ice and water. He also called attention to the variations of 
Kniefda fruticosa in its fruit and pedicels. 
■ Mrs. Britton and Miss Mulford were of the opinion that the 
prevailing Houstonia was certainly different from ordinary forms 
of H. purpurea or H. longifolia. Upon investigation Dr. Britton 
discovered it to be densely papillose-glandular, with other marked 
characteristics. 
A very fine clump of Carex scabrata was also reported. 
Mr. Van Pelt and Mr. Crawford reported a great colony of 
tall terrestrial Isoetes out on the high rocks opposite the Slab. 
They had the same general appearance as Eleocharis Engelmanni, 
due to the length of the erect and rigid leaves. The only species 
approaching it in general character, L Engelmanni valida, was 
reported some years ago from vicinity of Smithville, Lancaster 
County, some distance away. (The river plant was sent to Pro- 
