152 Cryptogams or Flower less Plants — Alga. 
their aquatic habit, but presenting some anomalous and complex conditions in their reproductive organs. 
The species occur wholly submerged and are frequent in fresh or brackish waters all over the Globe. 
The stem is usually slender, consisting of long simple cells end to end, giving off whorled branches at 
the joinings {Nitella), or the cells of the axis are wound around spirally by several parallel secondary 
filiform cells {Chara). 
The reproductive organs are of two kinds : 1. Globose orange-coloured' capsules, each consisting 
of 8 concave triangular plates accurately fitted to each other by their margins, from the centre of each 
of which there projects into the cavity of the capsule a filament bearing a bundle of antheridia. The 
antheridia when mature liberate by rupture microscopic spiral,, motile antherozoids. 2. Oblong capsules 
(called nucules), consisting of a central ellipsoidal cell enveloped by 5 spirally-wound cells, the tips of 
which project at the apex. In this nucule the single spore is developed by contact of the antherozoids. 
Species of Nitella are well adapted, from the large size of the cells of the stem, for demonstrating 
the motion of the cell-contents, rendered obvious under the microscope by longitudinal currents which 
carry coloured granular matter in their course. 
