Genus i. 



QUILLWORT FAMILY. 



53 



8. Isoetes Eatoni Dodge. Eaton's 

 Quillwort. Fig. 125. 



Isoetes 'Eatoni Dodge, Ferns and Fern Allies of 

 New Eng. 39. 1896. 



Amphibious from a large trunk \'-\\' in 

 diameter. Leaves of the submerged plant 30- 

 200, varying in length up to 28', marked with 

 an elevated ridge on the ventral side ; leaves 

 of the emersed plant shorter, 3-6; stomata 

 abundant; peripheral bast-bundles irregular in 

 occurrence or often wanting; velum covering 

 i of the sporange, . polygamous ; sporanges 

 large, 0.4' by 0.15', pale spotted; macrospores 

 small, 300-450 /"■ in diameter, marked with con- 

 volute labyrinthine ridges and cristate on the 

 angles of the inner face ; microspores 25-30 /"■ 

 in diameter, minutely tuberculate. 



In mud flats, New Hampshire to New Jersey. 



9. Isoetes Dodgei A. A. Eaton. Dodge's 

 Quillwort. Fig. 126. 



Isoetes Dodgei A. A. Eaton, Fern Bull. 6 : 6. 1898. 

 Isoetes canadensis A. A. Eaton, Proc. U. S. Nat. 

 Mus. 23: 650. 1901. 



Plant amphibious from a bilobed trunk. 

 Leaves 10-75, 8'-i8' long when submersed, 

 erect, or spirally ascending when scattered ; 

 emersed leaves 4'-6' long, tortuous and often 

 interlaced, with numerous stomata and usually 

 4 bast-bundles ; velum narrow, covering i to I 

 of the sporange ; sporanges thickly sprinkled 

 with light brown cells ; macrospores more 

 numerous on submersed plants, globose, 500- 

 675 ^ in diameter, sparsely covered with ir- 

 regular crests which at maturity separate into 

 irregular groups leaving bare spaces, serrate 

 or spinulose at the top ; microspores more 

 numerous on emersed plants, 22-44 ft ashy, 

 papillose or wrinkled. 



Growing in mud flats, East Kingston, New 

 Hampshire. 



10. Isoetes Engelmanni A. Br. Engelmann's 

 Quillwort. Fig. 127. 



Isoetes Engelmanni A. Br. Flora, 29: 178. 1846. 

 Isoetes Engelmanni fontana A. A. Eaton, Fern Bull. 13 : 



52. 1905. 

 Isoetes Engelmanni gracilis Engelm. in A. Gray, Man. 



Ed. 5, 677. 1867. 

 Isoetes Engelmanni vahda Engelm. in A. Gray, Man. 



Ed. 5, 677. 1867. 



Amphibious, usually partly emersed when mature. 

 Leaves 25-100, light green, quadrangular, tapering, 

 9-20' long, bearing abundant stomata; peripheral 

 bast-bundles present ; monoecious ; sporange oblong 

 or linear-oblong, unspotted ; velum narrow ; macro- 

 spores 320-750 f- in diameter, covered with honey- 

 comb-like reticulations; microspores 24-30 p long, 

 mostly smooth. 



In ponds and ditches, rooting in mud, Maine to Vir- 

 ginia and Pennsylvania, Illinois and Missouri. 



