40 
Ohio Biological Survey 
tracts within the family may be seen by consulting our hgures (Pis. Ill 
and IV), and the measurements given in the descriptions of the sex 
organs. Our work on these areas in Syneclioblastus illustrates the 
rather slight dififerences within the species studied from this genus. The 
differences in size of ordinary spermatia and the internal male repro¬ 
ductive cells found in certain of the Collemaccae may be seen by com¬ 
paring Figs. 14, 20, 21, 22, and 23. 
One of the writers of the present paper had Miss Bachman’s material 
for examination during the progress of her studies. It seemed certain 
enough that she was working on Collema pulposuni until the peculiarities 
with respect to the morphology and the behavior of the sex organs were 
discovered. It then became apparent that her plants could not be 
Collema pulposiim, if those previously studied by Stahl (7) and 
Sturgis (8) are this species. Unfortunately, the reproductive areas can 
be studied successfully from herbarium material so seldom that it is 
doubtful whether microscopic study of the type of the genus Collema 
and the type specimen of Collema pulposum would help to decide which 
plants are like the types with respect to the sexual tracts. To attempt to 
treat in this paper the material with internal sex organs found in Ohio 
would be premature. One of the writers will continue with taxonomic 
studies of the material already examined by us from Wisconsin, Iowa, 
Alinnesota, Ohio, Missouri, and New York, with any other that we may 
discover, while the other author pursues further cytologic investigations. 
The thalli of members of the Collemaceae are composed entirely of 
hyphae. The hyphae are commonly long-celled and loosely interwoven in 
such fashion as to form a mycelial structure, which usually composes 
the larger portion of the somatic areas. In the hypothecia and the 
exciples, the hyphie are closely interwoven. In these areas, the cells of 
the hyphae may be long, or they may be approximately isodiametrical and 
so closely placed as to exclude interhyphal spaces. In Leptogiuin and 
Mallotium there is a distinct cortex, usually one layer of cells in thick¬ 
ness (Fig, 1 ), composed of a layer of roughly isodiametric end-cells of 
hyphae which extend from the dorsal to the ventral surface. Lindau (5) 
has proposed the term plectenchyma for the densely interwoven 
parenchymatoid hyphal tissues of fungi and has distinguished two kinds, 
the paraplectenchyma with cells roughly isodiametrical and the proso- 
plectenchyma with the cells more or less elongated and the ends narrowed. 
The paraplectenchyma is found in the cortices in certain genera of the 
Collemaceae and in the exciples and the hypothecia of certain species. 
The prosoplectenchyma is rarely seen in the plants which we have studied. 
