THE AQUATIC QUILLWORTS. 227 



distinct to be called a species, and it has recently been 

 reduced to a variety of Isoetcs Tuckcruiaui. 



Under the name of Isoctes lieterospora Mr. A. A. 

 Eaton has described a species from Mount Desert 

 Island, Maine, which the author would be inclined to 

 call a form of Isoetes Tucker mani also. In this form the 

 leaves are two or three inches long, from fifty to seventy- 

 five in number, and lack stomata. The sporangia are 

 thickly spotted and are one third or more indusiate. 

 The megaspores are normally 540^ to 675 p in diameter, 

 but specimens with a diameter of 1150^ are often found. 

 They are densely covered with thick, jagged, anastomos- 

 ing crests, often honeycombed below. The microspores 

 are 30^ to 40^ in length, dark brown, and papillose. The 

 megaspores often have neither commissures nor equato- 

 rial ridge. Occasionally what answers to the latter is 

 present, but misplaced, often enclosing but a small area 

 on one side of the spore. This seems to indicate an 

 aberrant plant. Thus far it has been found in but two 

 localities, both on Mount Desert Island, Maine. 



Bo lander s 



In the western part of America the lakes occasionally 

 contain a species of Isoetes called Bolander's quillwort 

 (Isoetcs Bolanderi], which by the single item of the spore 

 markings may be separated from all our Eastern species. 

 In its own region, however, it is easy to confuse with 

 other species, which are marked much like it. In 

 appearance this species has a resemblance to the mem- 

 bers of what, for convenience, may be called the Isoetcs 

 ecJiinospora group. Its leaves are erect, bright green, 

 from five to twenty-five in number, and from two 

 to four inches long. They generally have few stomata 



