380 BOTANICAL GAZETTE [way 
culture, and the wild gametophytes were compared with them. 
They resembled closely the two latter, but were definitely different 
from E. arvense. 
In eastern Nebraska but two other species of Equisetum are 
known, E. robustum and E. variegatum, according to FirzPATRICK 
(4). Of these E. variegatum is rare; E. robustum is seldom found | 
except along the banks of the Missouri River and its larger tribu- 
taries. The gametophytes found on the river banks at Florence 
and South Sioux City were slightly larger than the others and might 
belong to this species. FirzpATricK, however, who examined the 
young sporophytes of all of the collections, failed to find on these 
evidence of the characters of E. robustum. Like those of all the 
other Nebraska gametophytes, he found that they resembled more 
closely E. /aevigatum. ‘These last bore so many large sporophytes 
that the gametophyte tissue was badly disorganized and of little 
use for study; consequently the microscopic studies were limited 
to the gametophytes from Tekamah, Pilger, and Lincoln. As at 
these places E. robustum is not present, and as the gametophytes 
do not resemble E. arvense, they are undoubtedly E. laevigatum. 
The gametophytes from Osborn, Indiana, are without question 
E. arvense. Adult plants of the species occurred near by, and the 
gametophytes agree with those grown in culture. Those from 
Manhattan, Kansas, Iowa City, Iowa, and Reno, Nevada, were not 
seen by the writer, nor were those from Peru, Nebraska. Abundant 
specimens from the other localities, however, have been examined.” 
Gametophytes 
The gametophytes appear as circular cushions (figs. 1-5, 7; 10, 
and text fig. 1) varying in diameter from 1 mm. to 1 cm. They 
are a dull green with a slight brownish tint, making them incon- 
spicuous as they grow on the wet soil. In many cases the writer 
looked at a given spot several seconds before her eye differentiated 
the form of the gametophytes, even where there were some of the 
larger ones. This may account in part for their not having been 
found more frequently. 
Sections made by STEVENS i Pe gametophytes found by him at Manhattan, 
Kansas, have been examined. ese agree entirely with the gametophytes of 
E. laevigatum. 
