78 MEDICAL BOTANY. 



Class V.— Acrogens or Acrogenons Plants. 



Flowerless plants with a regular stem or axis growing from the apex, com- 

 posed of cellular tissue and vessels ; usually furnished with leaves. Spores 

 contained in a theca or case. 



Group LII. — Filicales. 



Vascular. Spore cases marginal, or dorsal. 1 -celled. Usually sur- 

 rounded by an elastic ring. Spores of one kind only. 



Order 120. — Polypodiace^e. — Spore cases ringed, dorsal or marginal, 

 splitting irregularly. 



Group LIII. — Lycopodales. 



Vascular. Spore cases axillary or radical, 1 or many-celled. Spores of 

 two sorts. 



Order 121. — Lycopodiace^e. — Spore cases 1-3 celled, axillary; repro- 

 ductive bodies similar. 



Class VI,— Thallogens or Thallogenous Plants. 



Plants wholly formed of cellular tissue, with no distinction of stem or 

 leaves. Not reproduced by buds, or by organs analogous to flowers. 



Group LIV. — Algales. 



Cellular, flowerless plants, nourished through their whole surface ; living 

 in water ; propagated by zoospores, coloured spores, or tetraspores. 



Order 122. — Fucace^e. — Cellular or tubular, unsymmetrical bodies, mul- 

 tiplied by simple spores formed externally. 



Order 123. — Ceramiace^e. — Cellular or tubular unsymmetrical bodies, 

 multiplied by tetraspores. 



Group LV. — Fungales. 



Cellular, flowerless plants, nourished through their thallus ; living in 

 air ; propagated by colourless or brown spores, and destitute of green go- 

 nidia. 



Group LVI. — Lichenales. 



Cellular, flowerless plants, nourished through their whole surface ; living 

 in air; propagated by spores usually enclosed in theca, and always having 

 green gonidia. 



