THE OLDER SPOROPHYTE 191 



much the same as that described for Dana a, since the appearance of the longitudinal 

 sections in Marattia is exactly like that of corresponding stages in Dancea. The 

 apex of the stem, however, is much broader than in Dancea. There is in the middle 

 of the apical region a cell which from its size and position may be pretty certainly 

 denominated the apical cell (fig. 174, C). There is present a strand of procam- 

 bium which ends abruptly a short distance below the stem apex. This strand 

 probably represents the primary commissural strand, which, as in Dancea, is in 

 all probability a truly cauline bundle and has no direct connection with the leaf 

 traces. In the central region of the stem there are now several large mucilage 

 ducts, but tannin cells are still absent. In the roots, however, the tannin cells are 

 abundantly developed. 



Farmer and Hill's brief account of the development of Marattia fraxinea agrees 

 with my own observations so far as they have gone, except for the interpretation 

 of the vascular bundles. The "protostele" found in the lower part of the stem is 

 undoubtedly the common bundle of the primary root and the cotyledon, and the 

 open "siphonostele" is really made up of separate leaf traces, which anastomose 

 at certain points to form the large meshes of the very open dictyostele. Farmer and 

 Hill call attention to the fact that the "foliar gaps" are much wider than in Angi- 

 opteris, and in consequence the separate strands, seen in section, form a circle of 

 apparently quite separate bundles, evidently closely approximating the condition 

 found in Dancea and Kaulfussia. Farmer and Hill do not make it quite clear that 

 the commissures which they found developed later, connecting the strands of the 

 dictyostele, were really parts of the central cauline strand, but they presumably 

 assume that such was the case, as this is explicitly stated in the case of Angiopteris, 

 which they also studied. The structure of the bundle in the latest stage described 

 by Farmer and Hill agrees pretty closely with the condition described by Kuhn in 

 the youngest specimens which he studied, where the stem was about a centimeter 

 in diameter. 



1 he early leaf traces, as in the other Marattiacea?, are single, but later on double 

 traces are formed. According to Farmer and Hill, the two bundles of the leaf trace 

 unite before joining the vascular cylinder of the stem. No material was available 

 for a further study of the development of the bundle in M. douglasii, but it probably 

 agrees with that of M. fraxinea. 



Several young plants of M. alata were examined for comparison with the young 

 germ plants of M. douglasii. The specimens in question (fig. 175) had arisen as 

 adventitious buds upon the old leaf bases which had become separated from the 

 stem. This manner of formation of the young plants is very common in this species 

 (see plate 12, A). In one of these young plants, in which the stem was about 4 

 centimeters long and 1.5 centimeters in diameter, exclusive of the leaf bases, tin 

 oldest expanded leaf had a petiole of about 8 millimeters in diameter. In these 

 young plants there is usually only one leaf expanded, so that they have a very different 

 appearance from the fully developed sporophyte with its crowded circle of leaves, 

 and these monophyllous plants remind one very much of sterile specimens of some 

 of the larger species of Botrychium (plate 12, B). A section of the petiole of this 

 specimen showed ten vascular bundles arranged in a circle, within which, on the 

 ventral side, were two other bundles. The section resembled almost exactly that 

 of the petiole of a fully developed leaf of Helminthostachys. At the base of the leaf 

 are the two very conspicuous stipules, one of which overlaps the other. These 

 stipules are connected by a commissure which joins tin two stipules near the base 

 and is entirely concealed within the cavity formed bv the overlapping stipules, 

 but can be seen on raising these, as a hood-like membrane, overarching the next 



