SPECIAL MORPHOLOGY : LYCOPODIACE^. 



191 



knowing the history of their development, 

 that the sporocarps are definite modifications 

 of the parenchyma of the leaf. An acquaint- 

 ance with the mode of their development 

 leads, however, to the same results. In Iso- 

 etes we are still deficient in more exact inves- 

 tigations. It seems to me, however, that, con- 

 sidering the exactly similar structure of the 

 large and small spores, the difference of size, 

 and the investment of (probably) carbonate 

 of lime, together with the somewhat greater 

 complexity of the fruit owing to the persist- 

 ence of the cellular tissue, are matters of 

 very subordinate importance. Here, too, we 

 must seek for elucidation solely from the his- 

 tory of development. 



B. In some of the Lycopodia we meet with another form of the 

 fruit, which is rounded, tetraedric, opens by a longitudinal cleft 

 into two trilobed valves, and encloses four large spores, which 

 consist of one spore-cell and a very tough investment covered with 

 warts or reticulate stria3. The contents, according to Bischoff*, 

 are a delicate cellular tissue. 



The large spores are certainly identical with the large spores in 

 Isoetes; and if even their contents be cellular, this must be merely owing 

 to a further stage of development, f 



106. The stem of the Lycopodiacece consists of a mass of rather 

 loose parenchyma, intersected by a central simultaneous ( 26.) 

 vascular bundle. This vascular bundle generally has the vessels 

 scattered through it in irregular lines and bands, and mostly sur- 

 rounded by a deposit of brownish thick-walled parenchyma. The 

 vascular bundles, passing into the leaves and lateral stalks, often 

 run in an oblique direction through the parenchyma, separating 

 from the principal bundle a long way below where they pass off 

 into the leaf. The leaves consist of several layers of roundish 

 parenchyma, intersected by a vascular bundle, and invested by an 

 epidermis exhibiting stomata on both surfaces. The wall of the 

 sporocarp has mostly two layers, the external one displaying flat 

 cells with tough curving lateral walls, and the inner thin-walled 



* BischofF, Die kryptogamischen Gewachse, p. 110. 



f The Lycopodiacece were the only cryptogamic plants against which the anther-mania 

 had not heen directed; when (Jan. 18. 1842) Link, not content with his discovery of 

 anthcridia in Lichens, likewise provided the Lycopodiacea: with antheridia, which he 

 maintained were the larger spores. (Froriep's Notices, vol. xvi. p. 74.) Men are 

 always nearest to a new stage of advancement when they have carried out a definite 

 folly in all its systematic completeness. Now, therefore, when there remain no further 

 antheridia to be discovered, it is to be hoped that this worn-out plaything will be cast 

 aside. 



'* Lycopodium annotinum. A, The spore -leaf, with the capsule; B, the same in a 

 longitudinal section ; C, spores (semen Lycopodii). 



