GENERAL MORPHOLOGY 



305 



at Mariemont in Belgium, are about to be described by Mr. Kidston : to 

 him I am indebted for the information that this large Lycopod bore its 

 sporangia associated with the leaves of certain portions of the stem, without 

 any cone-formation, or alteration of the form or disposition of the leaves 

 which bear them : the fertile and sterile portions are distinguished only 

 by the presence or absence of sporangia. It is, in fact, a typical repre- 

 sentative of the " Selago " type, but of dendroid dimensions. In this 

 connection it is interesting to note that Solms Laubach mentions certain 

 " remains of great size, remarkable for the unusual thickness of the axis 

 classed by Lesquereux with Lepidophloios. Weiss also has described 

 a similarly colossal cone as Lomatophloios macrohpidotiis, but, unfortunately, 



- 



ic.- 



n. 



-~ 



sp. w. 



FIG 153. 



Lcfiidostrobus. Diagram showing axis and sporophylls in radial section. a = axis of 

 strobilus ; = sporophylls and sporangia; .r = stele; i, c = inner cortex; in, c=middle 

 cortex ; o, c = outer cortex ; / = pedicel ; / = Iamina of sporophyll ; /z = ligule ; /, /=Ieaf- 

 trace ; sp, / = \vall of sporangium. (Enlarged after Maslen, from Scott, Studies in 

 Fossil Botany.) 



there is no detailed account of it. The enormous size of the axis in 

 these specimens gives rise to the suspicion that the fructification was not 

 confined to special fertile shoots, but might occasionally appear on the 

 leaves even of the main stem, which then increased in thickness, much 

 as we see in the present day in the female flower of Cycas, and mutatis 

 mutandis in Lycopodium Selago. We naturally ask, on what sort of scars 

 could such cones be seated as lateral organs?" 1 Kidston's description of 

 Pinakodendron shows that the " Selago " condition did actually exist in 

 dendroid types, and thus resolves the difficulty. A similar condition is 

 shown by the small Lycopodites ciliatus, Kidst., from the Middle Coal 

 Measures, 2 while the still earlier Lycopodites Stockii (compare Fig. 147 

 above) also has its sporangia associated with leaves of the foliage type. 

 Finally, the imperfectly known Lycopodites Reidii, from the Devonian of 



^Fossil Botany, Engl. edn., p. 235. 

 2 Trans. Nat. Hist. Soc., Glasgow, vol. vi., p. 37. 



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