56 PALiEONTOLOGICAL BOTANY. 



F. Spn'pS -1 -2 -3- _5_ _8_ 1_3 2J. pfp 

 J^. KOt;ilt;&, 2) 5J 71 125 19J 31? 5 0J^^^' 



(13.) Leiy'idodendron (from Dr. Rankin's collection). About |- 

 inch in diameter. Secondary spirals 12 D, 19 S, 31 D. 

 Divergence = |-^. 

 F Sprips -1 -3_ _iL_ __7_ ii jLA etc 



(14.) Lepidodendron elegans (Possil Ironstone). About Ij 



inch in diameter. Secondary spirals 10 S, 13 D, 23 S, 



36 D. Divergence = ^. 

 (15.) Lejndodendron (Possil Ironstone). About 2 J inches 



in diameter. Secondary spirals 23 S, 36 D, 59 S, 95 D. 



Divergence = yYt- 



From the above it is evident that the phyllotaxis of 

 Lepidodendron is extremely variable, as much so perhaps as 

 that of those most variable plants, in this respect, the Cacti. 

 It is also clear that what has been enmiciated by Professor 

 Haughton (Manual of Geology, Lond. 1866, pp. 243, 245) 

 as the law according to which the leaves of paleozoic plants 

 were arranged — viz. that of alternate whorls — does not apply 

 to these ancient Lycopods. Lepidodendron aculeatum is 

 noted by Naumann as exhibiting an /y arrangement. (Pog- 

 gendorff, Annalen, 1842, p. 5.) Professor Alexander Braun 

 (Nov. Acta Ac. C. L. C. xv. I, pp. 558-9), speaking of the 

 excessive deviation from ordinary arrangements in Equise- 

 tacege (including Calamites), compares them in this respect 

 with Lycopodiacea3 (including Lepidodendron), saying that 

 in these two families " the utmost limits of the domain of all 

 leaf-arrangement appears to be attained." 



Lepidophyllum is certainly leaves of Lepidodendron, the 

 different Lepidophylla belonging to different species of the 

 genus. The slender terminal branches are noticed under the 

 name of Lycopodites. In coal from Fordel Mr. Daw has 

 detected innumerable bodies (Plate III. Figs. I, 2, 3) which 

 have been shown to be sporangia. (Balfour, Trans. Roy. 

 Soc. Ed. xxi. 187.) On their under surface Mr. Carruthers 

 has observed a triradiate ridge (Plate III. Fig. 4). (Geological 

 Magazine, 1865, vol. ii. p. 140.) These sporangia have been 



