\28 



( 'itvei's : Xoh's on J 'orkshire Bryophv/cs. 



The shoot of P. RhI/su, wWxchis about i cm. in length, is 

 rougiily triang-ular in outHne, liaving a basal cylindrical stalk- 

 like portion, 3—5 mm. long-, and spreading- out above into 

 a fan-like expansion, sometimes forked once in front (Fig-, i). 

 The broad, flattened portion bears on its upper surface numerous 

 thin lamellae or leaves, which are arrang-ed in two lateral series 

 and run obliquely outwards and forwards, each starting- from 

 near the middle line and almost reaching- the marg-in of the 

 plant. The cylindrical basal part of the stem g-rows obliquely 



upwards through 

 the sand in which 

 it is embedded, 

 whilst the flat- 

 tened leaf-bear- 

 ing upper portion 

 spreads out hori- 

 zontally over the 

 surface. The 

 basal portion is 

 nearly circular in 

 cross- section 

 (Fig 2, I.) and 

 consists of prac- 

 tically uniform 

 tissue, the super- 

 ficial cells bear- 

 ing r h i z o i d s , 

 which s p r i n g 

 from almost the 

 whole of the 

 stem-surface. In 

 long-itudinal sec- 

 tions, the central 

 cells are seen to 

 be longer and 

 rather narrower than the outer ones, and their walls show 

 niniierous oval or slit-like pits. There is, however, no definite 

 conducting strand, and on placing plants with the lower end 

 dipping into coloured liquids, it was found that the staining 

 solution passed with uniform rapidity through the central and 

 peripheral tissues. 



An interesting feature observed in the Coatham plants is the 

 occurrence of abundant branching fungal hypha^ in the stem. 



N.-itiiralist, 



Fig. I. — Plant as seen from above. 



