442 HOFMEISTER, ON THE HIGHER CRYPTOGAMIA. 



Ptilidium ciliare — must be excluded from the category of 

 plants having a two-edged terminal cell of the stem. 



Note on the Cell-multiplication of the Apex of the Stem, 

 in the Leafy Jungermannia:. 



The end of the stem in vigorous shoots of Jungermannia 

 bicuspidata exhibits, when viewed from above, a three- 

 sided apical surface of the terminal cell, and an arrangement 

 of the cells adjoining the latter, which leads to the con- 

 clusion that the cells of the second degree are formed 

 by the production of septa in the apical cell parallel to 

 each one of the three plane lateral surfaces. The order of 

 succession of the cells of the second degree represents a 

 spiral. All those Jungermanniae which I examined which 

 had inferior leaves, and consequently trilinear phyllotaxis, 

 exhibited a similar state of circumstances — for instance, 

 Alicularia scalaris, Calypogeia Trie ho manes, Lepidozia 

 reptans, Frullania dilatata, Madotheca platyphylla. The 

 same was the case also with another Jungermannia — besides 

 J. bicuspidata — with bilinear-leaves, viz. JPlagiochila as- 

 plenioides. In the latter — as in J. bicuspidata — a leaf 

 originates out of each cell of the two longitudinal rows of 

 cells of the second degree which are turned upwards to- 

 wards the creeping stem. Each of the cells of the longi- 

 tudinal row of cells of the second degree which occupies 

 the under surface of the stem, developes from its fore-edge 

 a transverse row of two- or three-celled hairs with elongated 

 clavate terminal cells, which hairs soon fall off. 



