CUTICLES OF CYCADEAN EEONDS. 



187 



placed at right angles to the adjacent veins. The stomata are numerous, about 120 per 

 sq. mm. Small papillae occur on many of the epidermal cells, but are not so conspicuous 

 as in JD. Johnstrupi. The structure of the stomata appears somewhat complicated 

 owing to the presence of what seem like small thickened outgrowths or papillae from 

 the surface above the guard-cells, and which are shown in PL 19. fig. 8, where the 

 guard-cells have been by some means pulled apart. In other cases they appear to 

 overlap the central space, as shown in PI. 19. fig. 6, and PI. 20. fig. 7, or give the 

 impression of the guard-cells interlocking with each other, as mentioned by Prof. Natliorst. 

 These projections are probably of a nature very similar to those observed in the case 



i 



of Ftilophyllum pecten {of. PI. 19. fig. 1). Sometimes they are not visible {cf. PI. 19. 

 fig. 7), being probably on the under side of the preparation; in this case the thickening 

 patches are very comparable to those in Otozamites. On either side of each stoma are 

 subsidiary cells, somewhat thickened and often much elongated {cf. PI. 19. figs. 6-8). 

 In preparations mounted with the lower side of the stomata uppermost, the latter seem 

 to have the same form as in several other examples of this group, the ventral patches on 

 the guard -cells being somewhat thinner. 



Anomozamites (Wielandiella) Nilssoni (Phill.), n. comb. 



Leaves of an Anomozamites form have been found in Yorkshire near Gristhorpe, 

 Marske, and Hoseberry Topping. They are very similar in shape to those of 

 Wielandiella angustifolia, Nath., and may well have belonged to plants bearing floral 

 structures similar to those found by Nathorst in connection with his species; such 

 structures are not, however, yet known with certainty from England, though stems have 

 been found which are almost identical with those of the Ehsetic plant. The cuticular 

 preparations obtainable from the Yorkshire Anomozamites leaves are excet.'dingly 

 beautiful, and show clearly the epidermal and stomatal characters. The leaves from 

 the Lower Estuarine Series at Marske differ slightly from those of Gristhorpe in the 

 possession of numerous spherical papillae on their lower cuticles ; the stomata are also 

 slightly smaller. 



In the specimens studied the upper epidermis is very uniform, and is composed of 

 more or less rectangular cells ; the courses of the veins are not clearly marked off, but 

 occasionally they are indicated by lines of slightly more elongated cells. The cell-walls 

 are again sinuous or zig-zag, but the folds have a different form from those in the other 

 genera, each of the ridges and grooves beingangular rather than nail-shaped or rounded ; 

 each point appears to possess a small pad of cutiu. The upper epidermis is devoid of 

 stomata. In some preparations the cuticle from the rachis of the frond is also seen ; 

 this has regular rectangular cells with straight walls, and occasional structures like 

 rudimentary stomata. The lower epidermis has a structure similar to that of the upper, 

 but the cells are less regular, and the stomata are irregularly scattered (cf. PI. 20. fig. 8J. 

 The courses of the veins are seen, though not very clearly, and no stomata lie upon 

 them. There are about 70 stomata per sq. mm., and their form is very clearly seen in 

 most examples. It is shown in PI. 19. fig. 5, and PI. 20. fig. 8. The central slit is 



SECOND SERIES. — BOTANT,^TOL. VIII. 



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