404 Fr. J. Mathiesen. 



cell, in the same direction (Fig. 14, C). The stalk-cell of the 

 latter type of hair rests upon the connecting parts of 4 — 8 

 epidermal cells, which are produced by the division of a 

 single cell, viz., the epidermal cell which has been the mother- 

 cell of the glandular hair. Below the stalk-cell small, circular 

 intercellular-spaces are formed between the lateral walls of the 

 cells of the epidermal layer (cf. Fig. 14, C and D; in D that 

 part of the lateral walls of the epidermal cells which lie under 

 the stalk-cells, is indicated by dotted lines — the dotted circle 

 inside the head of the small glandular hairs indicates the 

 outline of the stalk-cell). 



These large, peltate glands appear, therefore, to belong 

 to the same type as the "Schilddriisen" of Lathraea (and 

 Bartschia), the development of which has been so thoroughly 

 described by Scherffel; the intercellular spaces in the layer 

 under the stalk-cell have not been perceived by Hovelacque 

 or Wettstein. 



The small glandular hairs belonging to type 1 are also 

 found in other piaces on the leaf, but nowhere in such abun- 

 dance, as in the concavities on the under surface of the teeth. 



Glandular hairs with 1 — 2 celled head and multicellular 

 stalk (Fig. 14, F), such as those required for the diagnosis 

 of species, are found both along the margin of the leaf and 

 also — but scantily — upon the lower surface. 



Non-glandular hairs occur upon both leaf-surfaces, and 

 are especially numerous towards the margin and on the 

 veins; they are most frequently one-celled, but can also be 

 2 — 3 celled, pointed, and have fme cuticular striations (Fig. 

 14, A, C and G\ C and G are seen in optical section; the 

 thickness of the walls is evident from the figures). The epi- 

 dermal cell or cells (2 — 4) which bear them are distinguished 

 from the surrounding cells by having less strongly undulating 

 lateral walls, and outer-walls which are more or less strongly 

 arched outwards. 



