Ig5 THE MARATTIALES 



rhizome of Kaulfussia presents almost the exact appearance of a similar section of 

 Ophioglossum. 



In a rhizome having a diameter of about a centimeter twelve bundles shovi^ed 

 in a cross-section taken through the internode, one of these being the medullary 

 strand. The section of a petiole of a leaf taken from the same plant is shown in 

 fig. 171, C, and the structure of the section closely resembles that of the rhizome. 

 There were eight bundles arranged in a circle, within which were two medullary 

 strands. The cortical region was composed of several rows of brownish cells, prob- 

 ably similar to those in the outer part of the rhizome, and within these, separated 



Fig. I /o. 



Central bundle from a young sporophyte of Kaul- 

 fussia, showing two xylems. X150. 



Fig. 171. 



A. Rhizome of a large sporophyte of Kaulfussia. 5/, stip- 



ules; com, commissure. X~i. 



B. Section of rhizome. X2. 



C. Section of petiole. X2. 



from them by three or four rows of cells, was a conspicuous band of collenchyma, 

 a tissue characteristic of the leaves of most of the Marattiaceae. 



According to Kiihn, the bundles of the leaves are continued separately into the 

 cortex of the stem and do not unite into a single leaf trace. There are occasional 

 anastomoses of the vascular bundles of the petiole, quite like those in the stem itself, 

 and this becomes especially marked at the base of the leaf, so that the leaf trace (if 

 such it can be called) forms a hollow reticulate cone, quite equaling in diameter the 

 vascular cylinder of the stem itself, and attached to this by the open base, the sepa- 

 rate strands forming a crescent-shaped group when seen in section. The arrange- 

 ment of the bundles within the petiole itself and their method of junction with the 

 vascular system of the rhizome are very much like those in Ophioglossum pendulum. 



The vascular bundles, both in the petiole and rhizome, are concentric. The 

 endodermis is not recognizable and the central xylem is completely inclosed by the 

 phloem, sieve tubes being developed throughout. 



