e 
Price cr ARTICLES. 
SELECTED NOTES. III. 
(WITH SEVENTEEN FIGURES) 
EQUISETUM ARVENSE L.—Though Hofmeister’ has described in 
detail the sprouting spores of Eguisetum limosum and E. arvense, his 
figures of the latter are not so full but that another series might be of 
interest ; especially as. the method of development varies so greatly in 
this species. I have followed carefully the young prothallia of Z. 
arvense during a month of growth, and the figures here given illustrate 
their progress from day to day. In both &. Zimosum and E. arvense, Hof- 
meister finds that almost without exception there is first cut off in the 
germinating spore a comparatively colorless basal cell, which generally 
gives rise to the first rhizoid. In Z. arvense, however, he finds that 
there are numerous exceptions to this, the small basal cell often not 
elongating into a rhizoid, but remaining unchanged, while the large 
cell above produces the rhizoid. This variation was very rare in the 
spores sprouted by me, but such a case is shown in fig. 8. Some- 
times (jig. 6) the small cell was not cut off, but the rhizoid came directly 
from the base of the large cell. The first rhizoid is usually the only 
one for a long time, and in no case-did I find another, even in the 
oldest stages figured. The second wall is as a rule nearly parallel 
to the first in 2. arvense, while in &. limosum, according to Hofmeister, 
it is generally perpendicular or strongly inclined to it. 
Comparing figs. § and g, it will be seen that the greatest possible 
variation is met with. Both plants shown are of the same age, twenty- 
three days. The filamentous form (fig. 8) is very rare, and is not 
described by Hofmeister. But Campbell? finds that in £. ¢e/mateia 
“the first wall may be either vertical or transverse, and sometimes, 
but not often, there are several transverse walls, and a short filament is 
formed.”* Figs. 10-74 represent plants about one month old. ‘The 
largest is about old enough to produce antheridia. Later stages were 
not followed. 
* Vergleichende Untersuchungen der héherer Kryptogamen, Leipzig. 1851. 
? Mosses and Ferns 424, 
Equisetum. 
31 have not been able to see the papers of Sadebeck and Buchtien on 
60 . [JANUARY 
