200 BOTANICAL GAZETTE [SEPTEMBER 
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liated stems, produced new lateral shoots and quite a number of 
protonemata, hence the protonema and shoot production was 
not called forth by defoliation. 
12. FISSIDENS BRYOIDES, 
As in Ceratodon, all attempts to grow protonemata from the 
leaves of Fissidens were ineffectual. The leaves were kept for 
three months, and at the end of that time, although in apparent 
vigor, no protonemata had been produced. The stems, when 
stripped of leaves, produced rhizoids directly from the region of 
the leaf axils in both light and darkness. In the light, however, 
the rhizoids soon grew to possess a distinct protonemal charac- 
ter, but no protonemata originated directly from the stem. The 
stems grown in the dark produced long, sparsely branched 
‘thizoids, which attained a length of about 1™ after a month of 
growth. When first examined they possessed only oblique cross- 
walls, but at this time nearly all showed alternately oblique and 
perpendicular walls. The oblique walls were the ones first formed 
and the perpendicular walls were produced later by intercalary 
division. The great regularity of the alternately oblique and 
perpendicular cross-walls was due to the fact that each cell had 
become divided by a perpendicular wall. This fact is mentioned 
since intercalary division is an exception to the usual mode of 
protonema and rhizoid growth, and since it affords another 
example of perpendicular cross-walls being produced in dark- 
ORES. 
No buds were produced from the protonemata grown from 
_ the stem, but the stem gave rise to buds, and that in a peculiar 
way. After one month of culture the stems grown in the light 
were found to have produced buds directly from the region of 
the leaf axils, without the intervention of any protonemata. A 
bud grown in this way is shown in fig. 53. A surtace cell 
from the region of the leaf axil produces a protuberance, which 
instead of growing out into a rhizoid or protonema divides 
directly to form a bud. This manner of bud formation was 
observed only in light cultures. Plants with the leaves still 
