146 OUR NATIVE FERNS AND THEIR ALLIES. 



or rarely trilobed base ; leaves 1 570, stout, 2' 6' long, pinkish 

 even when dry or rarely dark green ; stomata scattered found 

 only near the tips ; no peripheral bast-bundles ; monoecious or 

 becoming dioecious; velum covering one-fourth or one-third of 

 the sporange ; ligule round-ovate ; sporanges thickly sprinkled 

 with dark cells which are often collected in groups; macro- 

 spores 0.380 0.560 mm. in diameter, covered beneath with very 

 thick-walled reticulations, the openings appearing like little 

 pits ; reticulations elongate on the upper surface of the spore ; 

 microspores dark brown, 0.022 0.035 mm. long, densely reticu- 

 late and usually slightly papillose. In muddy banks of the 

 Pautuckaway River, Epping, and East Kingston, New Hamp- 

 shire. 



11. I. Eatoni Dodge. Amphibious from a large trunk 

 i' 4' in diameter. Leaves of the submerged plant 20 200, 

 varying in length up to 28', marked with an elevated ridge on 

 the ventral side ; leaves of the emersed plant shorter, 3' 6' 

 long, stomata abundant; peripheral bast-bundles irregular in 

 occurrence or often wanting; velum covering one-fourth of the 

 sporange ; polygamous ; sporanges large, 10 by 4 mm., pale, 

 spotted ; macrospores small, 0.3 0.4 mm. in diameter, marked 

 with convolute labyrinthine ridges and cristate on the angles of 

 the inner face; microspores 0.025 0030 mm. in diameter, 

 smooth or slightly papillose. In mud flats, East Kingston and 

 Epping, New Hampshire. 



12. I. Dodgel A. A. Eaton. Plant amphibious from a 

 2-lobed trunk. Leaves 10 75, 8' 18' long, when submersed, 

 erect or spirally ascending when scattered ; emersed leaves 4' 

 6' long, tortuous and often interlaced, with numerous stomata 

 and usually four bast-bundles ; velum narrow, covering from 

 one-fifth to one-fourth of the sporange ; sporanges thickly 

 sprinkled with dark brown cells ; macrospores more numerous 

 on submersed plants, globose 0.50.675 mm. in diameter, 

 sparsely covered with irregular crests which at maturity sepa- 

 rate into irregular groups leaving bare spaces, serrate or spinu- 

 lose at the top ; microspores more numerous on emersed plants, 

 0.022 0.040 mm. in diameter, ashy, papillose. In mud flats, 

 East Kingston, New Hampshire; Pennsylvania. 



13. I. Engelmannl A. Br. Leaves 25100, light-green, 



