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THE AMERICAN NA TURALIST. [Vol. XXXVl 1 1. 



gestive of that of Helminthostachys (Fig. 2, A, C), and the 

 position of the leaves and roots is much the same. The cyhn- 

 drical stelar tube with relatively small foliar lacunae in Helmin- 

 thostachys may perhaps be compared to the stele in the young 

 rhizome of Dan?ea, which, according to Jeffrey, is of much the 

 same type. (Jeffrey, /oc. n't., pp. 120, 121.) 



The most marked histological difference between the Marat- 

 tiaceje and the Ophioglossaceae is perhaps the occurrence of 

 conspicuous mucilage ducts in the former. These are, however, 

 also wanting in the other ferns. The circinate form of the 

 young leaves is probably associated with the great development 

 of tlu' lamina ot the leaf, but is certainly a difference of some 

 importance. 



To the labors of Bower we owe by far the most important 

 contributions to our knowledge of the development of the sporan- 

 gium that ha\e been made for many years. These enable us to 

 make a detailed comparison of all the developmental stages in 

 each group, and a careful study of his descriptions and figures 

 of the two groui)s in question have led me to a somewhat dif- 

 ferent result from that reached by him. 



The progression from tl^e sporangial spike of Ophioglossum 

 to tlienuieh branched sjiorangiophore of Botrychium or Helmin- 

 thostachys. with its numerous distinct sporangia, is comprehen- 

 sible enough ; but the relation of the sporangiophore of the 

 Ol)hioglossacea: to the sporangia of the other pteridophytes is 

 not so obvious. Bower believes {/oc. cit., p. 250) that all pteri- 

 doj)hytes may be reduced to the strobiloid type, this being 

 reduced to a single sporophyll in Ophioglossum. As we have 

 stated elsewhere, this theory seems hardly satisfactory when 

 ai)plied to the ferns, however probable it may appear for the 

 ptcridoi)hytes. The comparison of the sporangial spike 



ai^pears rather improbable, and it seems more in accordance 

 wuli the tacts to eonsider it an entirely distinct development, 

 derned dnet tly trom the whole upper part of the sporogonium 

 of the ancestral form. 



Bower's very complete account of the sporangia in Ophio- 

 glossum and the Marattiaceac suggests a possible point of con- 



