Halsted.} 172 [March 5, 
At the joints, whorls of leaves are produced which may or may not. 
be corticated. The leaves may be either simple, when they have a 
distinct main axis, and bear the sexual organs along the upper side 
(Chara), or compound, when they divide up into several parts, and 
bear the sexual organs in the forkings thus produced. (Nitella). At 
the node, in the axil of the oldest leaf (Chara) or the two oldest 
leaves (Nitella), a lateral branch arises, which repeats in all respects 
the structure of the primary stem. 
The sexual organs consist of the male body antheridium, (globule), 
and female organ, sporangium, (nucule); both of which may be borne 
on the same plant (monecious) or on different plants (dicecious). 
The spore produces a proembryo in germination. 
Nonsexual reproduction is by means of bulblets; branches with 
naked base, and proembryo-branches. 
1. Family NITELLEZ. 
Plants monecious or dicecious, without cortications and stipular ring. 
Leaves 5-8 in a whorl, with leaflets large and often many celled. 
Sporangia one to several, on a short basal cell, in the forkings of the 
leaflets; crown consisting of two superimposed whorls of five cells each. 
Covering of spore without calcareous incrustation. 
1. Genus NireLtia. Ag. em. A. Br. 
Plants monecious or dicecious. Primary leaflets all arise from the 
same node and are frequently repeatedly divided. Antheridia ter- 
minal, the basal cell small. Sporangia beneath the antheridia, single 
or in clusters. 
SYNOPSIS OF THE SPECIES OF NITELLA. 
Genus NiTELLA Ag. em. A. Br. Antheridia terminal. | 
A. Ultimate divisions of leaves one celled. 
1. Diecious. 
a. Fruit in loose clusters. NN. opaca Ag. 
b. Fruit in large dense heads. NV. capitata Nees. 
2. Monecious. 
a. Fruit in gelatinous heads. NV. gelatinosa A. Br. 
b. Fruit not in gelatinous heads. 
a. Sporangia beaked. N. flexilis Ag. 
6. Sporangia not beaked. | N. translucens Ag 
