214 



DE. AGNES AEBEE ON THE 



thin-walled cells forming the inner tissue of the keel, which are often much crushed. 

 The epidermis and also the hypoderma seem to consist, in places, of more than one layer 

 of cells ; but in spite of this irregularity, the general appearance, as seen in tangential 

 sections, is highly characteristic. It contrasts markedly, for instance, with the large- 

 celled epidermis and ahsence of hypoderma in L. oldhamius, Will., f. minor {cf. PI. 22. 



figs. 7 & 8 with PI. 26. fig. 40). 



The upturned lamina of the sporophyll consists, especially in its hasal region, of thin- 

 walled parenchymatous tissue (/., PL 22. fig. 6), hut sclerenchyma is not altogether ahsent, 

 and increases in amount higher in the lobe. The appearance of the lamina suggests that 

 it was slightly succulent. The cells towards the dorsal surface are relatively small, and 

 their radial arrangement, as well as the angular form which they assume in cases where 

 the tissue has hccome crushed or shrunken, indicate that periderm formation has come 

 into play {pd., PI. 22. fig. 6, PI, 24. fig. 20, and PL 25. fig. 29). There is occasionally a 

 slight appearance of a similar formation at the ventral surface of the sporophyll lamina. 



An interesting feature is the occurrence of delicate cellular outgrowths {l.o., PL 22. 

 fig. 6 and PL 25. fig. 30), which appear to arise from the inner surface of the downward 

 heel (or dorsal flap) which occurs at the hase of the sporophyll lamina. Unfortunately 

 the preservation is not sufiiciently perfect to make it possible to give an exact account 

 of the nature and arrangement of these structures. However, from a comparison of 

 the two sections in which they can he distinguished, I am inclined to think that they 

 consisted of cell-plates, two or three elements in thickness. 



The anatomy of the sporophyll trace during its passage through the pedicel is 



F 



illustrated in PL 22. fig. S and PL 25. fig. 28. The small compact xylem group, 

 consistinf?, in three cases in which the elements were counted, of less than a dozen 



1 



tracheides, is surrounded hy large transfusion elements, which are especially abundant 

 on the upper side of the bundle. These transfusion tracheides are very well developed 

 at the junction of lobe and pedicel. In the upturned lobe, the bundle presents the 

 same general appearance as in the pedicel, but the tracheides are fewer in number. 



(6) The Ligule. 



A ligular pit is visible in more than one case, and the body marked '* ? Z^." in PL 24. 

 fig. 20, may perhaps represent the ligule itself. 



(7) The Spoj^angium. 



The sporangium has the radially elongated attachment to the pedicel, which is one of 

 the characteristics of the genus Lepidostrohus . The distal and proximal ends of the 

 sporangial base are represented in PL 24. figs. 20 & 21. The attachment is of 

 considerable breadth, and a massive ridge of tissue is continued up into the base of the 

 sporangial cavity {sLr., PL 22. fig. 7, PL 24. fig. 21, and PL 25. figs. 26 & 27). This 



r 



may perhaps be interpreted as of the nature of sterilised sporangial tissue, since it is 

 bounded on either side by a continuation of the sporangium wall *, but, at the same 

 time, it is perfectly continuous with the parenchyma of the sporophyll. 



mature in the case of Z. oldhamius (Ji) and L. foUaceus. Maslen, A. J. 



('99), pp. 370 & 374, pi. 38. figs. 32 & 38. 



