12 Stopes, a Neiv Fern froui the Coal Measures. 



cells just outside the xylem ; these are probably the 

 phloem^ and they appear to surround the xylem on both 

 sides. In some places, between them and the cortex is a 

 darker streak of crushed cells, which probably represent 

 the endoderniis and pericycle in their normal position. 



Se\'eral of the small branchlets, the nature of which 

 is uncertain but which are possibly fine ramifications of 

 the rachis (see p. lo), shew an extremely simple stele, the 

 xylem, which alone is preserved, being a single solid mass, 

 sometimes with 3 groups of proto.xylem on the same side, 

 like a very simple case of the form once called R. triden- 

 tata. In its simplest terms, this type of stele appears in 

 the small branches of several ferns, and seems therefore 

 to be of little value as a criterion of specific affinity. 



In the small petioles {i.e. those which have recently 

 left the main axis) the cortex appears to be a simple tissue 

 of compact, probably rather thickened cells. In the larger 

 ones, however, there seems to be a distinct differentia- 

 tion into two zones, an inner one composed of thin-walled 

 tissue which in tangential section has almost the appear- 

 ance of" spongy parenchyma," and an outer one of rather 

 thick-walled cells i^Pl. 2, Fig. 2). Within the soft cells of 

 the inner zone in many of the petioles are to be seen 

 numbers of small circular or oval bodies, which have the 

 appearance of actual cell contents (see PI. 3, Fig. 9). In 

 some parts they are exceedingly crowded, and bear a 

 strong superficial resemblance to starch grains. Their 

 likeness to fungal spores, as preserved so frequently in 

 fossils, is also marked, but I incline to the view that they 

 are starch rather than fungi, on the following grounds : 

 Each little separate body is apparently unconnected with 

 its neighbours by any thread or filament, as it would be 

 if it were a fungal sporangium ; there are further no 

 obvious fungal hyphae which one would expect in con- 



