190 LYCOPODIALES [CH. 



this tissue occurred in a modified form, but even assuming that 

 the section figured by Maslen shows true phloem, an assump- 

 tion based on slender evidence, this is not sufficient justification 

 for the application of the term phloem to a tissue occupying 

 a corresponding position in vegetative shoots and distinguished 

 by well-marked histological features. 



The sporophyll-traces, as seen in the outer cortex in fig. 

 191, D, are partially surrounded by a large crescentic space, p, 

 which was origmally occupied by the parichnos. The sporangia 

 are attached along the middle line of the sporophyll and, as in 

 Lepidostrobus Brownii, a cushion of parenchyma projects into 

 the lower part of the sporangial cavity (fig. 191, A, a ; C, a). 



The diagrammatic sketch of part of a section in the Birmey 

 Collection reproduced in fig. 191, B, shows the position of the 

 ligule, I. No megaspores have been discovered in any speci- 

 mens of this type ; the microspores, which occur both singly 

 and in tetrads, have a length of 0*02 — 0'03 mm. 



The drawing shown in fig. 191, A, based on a section in the 

 Binney Collection, illustrates the general arrangement of the 

 parts of a typical Lepidostrobus. I have made use of this 

 sketch instead of that given by Maslen, as his figure conveys 

 the idea that the sporophylls are superposed, whereas, whether 

 they are verticillate or spiral, a radial longitudinal section 

 would not cut successive sporangia in the same plane. 



iii. Lepidostrobus Brownii (Brongn.). 



In 1843 a specimen of a portion of a petrified cone was 

 purchased by the British Museum, assisted by the Marquis of 

 Northampton and Robert Brown, for £30 from a French 

 dealer. This fossil, from an unknown locality, was briefly 

 described by Brown in 1851^ and named by him Triplosporites, 

 but in a note added to his paper he expressed the opinion that 

 the generic designation Lepidostrobus would be more appro- 

 priate. Brongniart afterwards named the cone Triplosporites 

 Brownii-, and Schimper^ described it in his TraitS as Lepido- 



1 Brown, B. (51). 2 Brongniart (68). 



■' Schiniper (70) A. p. 67, PI. lxii. figs. 13—29. 



