Manchester Memoirs, Vol. /. (1906), No. 10. 9 



larger petioles the stele becomes very narrow, the C being 

 somewhat laterally elongated and the ends more incurved, 

 its orientation as regards the main axis, however, remains 

 constant. 



In many cases, as the simple group of tracheides is 

 leaving the stele to pass out to the petiole, a smaller strand 

 separates from the main axis and bends away from the 

 stele to one side or other of the petiole strand. It runs out 

 through the cortex and forms what I take to be an 

 adventitious root (see Figs. 3 and 4). It is soon lost' 

 among the crowds of other rootlets which bend and 

 branch among the bases of the petioles. 



Of anything corresponding to a true " axillary shoot", 

 such as is found in Zygopteris and HyniefiopJiylliim, there 

 appears to be no trace. 



How soon the main petioles branched to secondary 

 ones it is not very easy to say, certainly it could not have 

 been very soon after leaving the main axis, as I can find 

 no case of the petiole stele branching to give off pinnules, 

 and in two cases only can I find branch steles within the 

 big petiole cortex. In one case this is in a fragment of 

 what must have been a very large petiole, lying in the 

 matrix remote from the main axis near the upper part of 

 the plant. This fragment is very well preserved, though 

 it is not repeated in the neighbouring two sections of the 

 series, so that it gives no information as regards the 

 method of branching. (See Slide T. 19.) The cortex is 

 in part beautifully preserved, and lying in it a few cell 

 rows from the outside to the left of the main stele is the 

 small branch bundle. It consists of a rather scattered 

 xylem group with some delicate soft tissue preserved, the 

 phloem apparently lies almost entirely to the outside, and 

 the whole is surrounded bj' a definite sheath of delicate 

 small cells, most of which are not well preserved, but 



