chidia \inear-lanceolate, acute, inflexed or involute, closely placed or tufted 
_ along the midribs of the leaflets, containing tetraspores in a double row. 
The colour is a dark brownish-red, becoming darker or blackish in the her- 
barium. The sadstance is coriaceous and tough, and in drying the frond 
scarcely adheres to paper, even under heavy pressure. 
A rare plant, with the aspect of the narrowest forms of Lenor- 
mandia spectabilis, but having a very different microscopic struc- 
ture and fructification, and easily known, with the help of a 
pocket lens, by the absence of the decussating lines conspicuous 
in Lenormandia, and the presence of the closely-placed, trans- 
verse striea. As yet I have seen very few specimens. The 
ceramidia are still a desideratum. 
Fig. 1. Rytrenit@a sIMpPLictFroiia,—the natural size. 2. Apex of a leaf 
(phyllodium) bearing stichidia along its midrib. 3. One of the stichidia, 
with its double row of tetraspores. 4. Cross section of the frond :—vari- 
ously magnified. 
