188 THE MARATTIALES 



from a medium-sized plant were tetrarch. Kiihn states that pentaich and hex- 

 arch roots also are formed. The reduced number of xylems in the root of Kaul- 

 fussia, as compared with the other Marattiaceae, is another indication of its probable 

 nearer relationship to the Ophioglossaceae, the structure of the root being very similar 

 indeed to that of Helminthostachys or Ophioglossum pendulum. 



THE SPOROPHYTE OF MARATTIA. 



The published observations upon the young sporophyte of Marattia are far 

 from complete. Kuhn (Kiihn I) has described the stem structure in young plants 

 of M. fraxinea, but it is evident that these plants were already too far advanced 

 to show the early arrangement of the bundles, as the stems he described had 

 reached a length of nearly 2 centimeters. Farmer and Hill (Farmer 3) have also 

 given some details as to the early stern structure in the same species. These young 

 plants, especially those described by Kiihn, have the stem relatively longer than is 

 the case either in M. douglasii, which I have studied somewhat in detail, or M. 

 alata, or M. sambucina, which I have also examined. In all of these species the stem 

 of the very young sporophyte is still quite short and very soon assumes the compact 

 globular form with the crowded leaves that it has in the adult sporophyte. It may 

 be said, however, that in M. alata the buds which develop upon the old leaf bases 

 have the young stem somewhat more elongated, but not nearly so much as Kiihn's 

 figures would indicate to be the case in M. fraxinea.'' 



In the youngest specimens examined by Kiihn the cross-section of the stem 

 showed a ring of bundles corresponding to the leaf traces and a central medullary 

 strand, the whole arrangement being very similar to that which is found in the 

 adult rhizome of Kaulfussia. This stage is also very similar to the condition found 

 in the young sporophyte of Dancea. 



Farmer and Hill describe the vascular skeleton of the very young plant of M. 

 fraxinea as a "siphonostele" with much larger foliar gaps than those found in 

 Angiopteris, and thus more nearly resembling Kaulfussia or Dancea. The leaf 

 traces are at first single, but the later leaves have double leaf traces, such as we have 

 described in Dancea and Kaulfussia. 



The writer has already published some details in regard to the young sporo- 

 phyte of Marattia douglasii (Campbell 3, 4), and some additional facts are here 

 added to those that have already been published; but as the series of specimens 

 available for study was not at all complete, further investigation is desirable to 

 complete the history of the development of the vascular system in Marattia. The 

 only material available for a study of the young sporophyte in M. douglasii was a 

 series of slides made a good many years ago from material collected on the island 

 of Kauai in the Hawaiian Islands. This material was supplemented by a small 

 number of very young plants of M. sambucina, collected in Java. Material of older 

 sporophytes of M. alata was collected in Jamaica in the summer of 1908. Un- 

 fortunately, all the preparations of M. douglasii, except the very youngest stages, 

 were longitudinal sections, so that it was difficult to follow out satisfactorily the 

 course of the vascular bundles in the later stages. 



Longitudinal sections of a young sporophyte before the cotyledon was com- 

 pletely expanded are shown in fig. 133. The section was cut nearly in the plane of 

 the cotyledon and the bent-over apex of the latter was cut so as to show plainly the 

 two lobes arising from the first dichotomy of its apex. The second leaf is already 

 formed and differs in no essential particular from the corresponding leaf in Kaul- 



* Since the above was written a paper has appear.-d (Charles l) describing the vascular system of the young sporo- 

 phyte of M. alala. The stele of the very young plant is described as a protostele which passes abruptly into a solenostele. 



