XV] LEPIDOSTROBUS 191 



strobus Brownii. The type-specimen is preserved in the British 

 Museum and the Paris Museum possesses a piece of the same 

 fossil. 



The central axis of the cone has a stele of the type 

 characteristic of Lepidodendron fuliginosum and L. Harcourtii, 

 and the xylem is surrounded by a thin-walled tissue described 

 by Bower' as possibly phloem ; but in the absence of longi- 

 tudinal sections it is impossible to say how far the tissue 

 external to the xylem agrees with that in Lepidodendron stems. 

 The sporophylls consist of a horizontal portion, to the upper 

 face of which the radially elongated sporangia are attached, one 

 to each sporophyll ; beyond the distal end of the sporangium 

 the sporophyll bends sharply upwards as a fairly stout lamina. 

 The wall of the sporangium is composed of several layers of 

 cells, as shown in a drawing published by Bower^; in the 

 interior occur groups of microspores, and from a ridge of tissue 

 which extends along the whole length of the sporangium 

 irregular trabeculae of sterile tissue project into the sporangial 

 cavity, as in Isoetes (fig. 191, H : cf. fig. 133, H). 



Further information in regard to Lepidostrobus Brownii has 

 recently been supplied by Prof Zeiller', who recognises the 

 existence of a ligule, and draws attention to some interesting 

 histological features in the tissue of the sporophylls^. 



Spores of Palaeozoic Lycopodiales. 



The calcareous nodules fi-om the Coal seams of Yorkshire 

 and Lancashire are rich in isolated spores, many of which are 

 undoubtedly those of Lepidostrobi. Examples of spores were 

 figured by Morris" in 1840, and their occurrence in coal has 

 been described by several authors, one of the earliest accounts 

 being by Balfour*. The drawings of Palaeozoic and recent 

 spores published by Kidston and Bennie' demonstrate a striking 

 similarity between the megaspores of existing and extinct 

 Lycopods, the chief difference being the larger size of the fossils. 



1 Bower (93). ^ Bower (94) PI. xlviii. fig. 93. ' ZeiUer (09). 



■" Zalessky has recently (08) described a large species of cone, Lepidostrobus 

 Berlrandi, 5 cm. in diameter. 



6 Morris (40). « Balfour (67). ' Kidston and Bennie (88). 



