Branched, simple cell-rows with intercalary growth. The organs
of reproduction are partly uni-and partly multicellular; in the
unicellular ones a cell without cilia is formed, which may be destitute
of a cell-wall, but has one nucleus (oosphere?), or which has a
cell-wall and contains several (generally four) nuclei (aplanospores?);
in the multicellular, monosymmetric swarm-cells with two cilia
(spermatozoids?) are formed. The fertilisation has not been observed.
Order 1. =Tilopteridaceæ.= _Haplospora_, _Tilopteris_.