Biological Papers. 291 



Order VI. OPHIOGLOSSALES: The Adder Tongues. 



(Homosporous Eusporangiate Stereocaulones.) 



Terrestrial herbaceous pteridophytes, with group-celled sporangia, in two 

 rows, on the lateral edges of the sporangiophore, the walls many 

 cells thick, transversely dehiscent. 



Sporophytes having each an erect frond-bearing stem, with one portion 

 (frond) adapted to chlorophyl work, another portion (sporophore) 

 adapted to fruit bearing. Sporophores (special fronds or branches 

 of fronds) bear spores all of one size (microspores) from bivalvular 

 sporangia developed from clusters of epidermal and subepidermal 

 cells in lieu of pinnae along the margins of special fronds or frond 

 branches (sporangiophores). 



Gametophytes (oophores) moncEcious, tuberous, within the surface of the 

 ground, devoid of chlorophyl, and said to be usually associated with 

 a symbiotic fungus-mycelium, but whether with injury or benefit 

 to the plant does not clearly appear. From oospores within the 

 oophore body arise the young sporophytes, which for a time nurse 

 upon the body of the oophore, then cast root and become erect in- 

 dependent plants. This is the beginning of the erect stem in vas- 

 cular plants and of differentiation between chlorophyl-developing 

 leaf and fruit-bearing branch; and although the stem and leaves 

 are only partially differentiated in the frond, yet it is a long step 

 toward an erect woody plant. 



There is but one family. 



Family 20. Ophioglossace^: Adder- tongue Family. 



152. Ophioglossum vulgatum L. Adder-tongue. Moist meadows 



and thickets, E. K. ; infrequent. May. (A S U) 



153. Botrychium virginianum Swz. Rattlesnake fern. Hazel 



thickets and wooded hillsides, N. E. K., west to Council 

 Grove; frequent. July. (A S U) 



154. Botrychium obliquum Muhlenberg. (5. ternatum Swz.) 



Grape fern. Moist woods and hillsides, Doniphan, Atchi- 

 son and Shawnee counties; rare. Sept. (S U) 



Order VII. HYDROPTERIDALES: The Water Ferns. 



(Heterosporous Leptosporangiate Stereocaulones.) 



Aquatic pteridophytes with horizontal stems and erect leaves with the 

 dichotomous nervation and circinate prefoliation characteristic of 

 ferns, and with spores that produce oospores without leaving the 

 sporocarp. Sporocarps have short stalks and are borne on cer- 

 tain modified leaves called sporophyls. Here the gametophytes are 

 more hidden than in any previous order of plants. 



Sporophores bear dimorphous spores, from sporangia developed from 

 single epidermal cells; the smaller size, called androspores, de- 

 velop into minute rudimentary gametophytic prothallia upon which 

 grow single antheridia; the larger, called gynospores, develop into 

 small globular oophores containing each an archegonium with its 

 ovum, which remains attached to the sporophore. Fecundation is 

 effected by an amoebic movement of the antheridial inner cell wall, 

 in the form of a closed tube, which protrudes from the androsporo- 



