ISOETACEAE (QU ILLWOKT FAMILY) 59 



c. Leaves reddish or olive-green. 



Gynospores averaging 440 ifi iu diameter, with small pits , . 4. I.foveolata. 

 Gynospores averaging old ft. in diameter, with thin irregular 



walls {i) I.f(yDeol<ita,y. plenospora. 



c. Leaves green d. 

 d. Gynospores with jagged crests. 



Gynospores averaging 600 /x in diameter; crests tall, mostly 



simple 5. /. nparia. 



Gynospores averaging less than 550 /m in diameter ; crests low, 

 simple or reticulated. 

 Leaves 1-2.5 mm. in diameter ; trunks 2-lobed ... 6. I. saecharaia. 



Leaves 1-1.5 mm. in diameter ; trunks 2-5-lobed (6) /. saccharata, v. Ameaii. 



d. Gynospores with slender or jagged spines. 



Leaves short, stout, spreading 7. /. echinospora. v. Braunii. 



Leaves long, fine, spiral (T) /. ecJdnospora, r. muricuta. 



§ 8. Plants of the extreme edges of ponds or streams, emersed most of the 



summer, with stomata and bast-bundles. — Palustres A. A. 



Eaton e. ' 



e. Bast-bundles 4. one at each front angle and one at each end of the 



dorsi-ventral partition f. 



f. Polygamous ; androsporangia rare ; gynospores appearing abortive. 



Bast-bundles often absent ; gynospores with labyrinthiform 



ridges " . . . 8. /. Eatoni. 



Bast-bundles always present ; gynospores with truncate col- 

 umns . . " . . . ' 9. 7. Gravesii. 



f. Monoecious. 



Gynospores with coarse irregular crests. 



Crests loose : sporangia slightly spotted 10. 7. Dodgei. 



Crests crowded ; sporangia densely spotted . . (10) 7. Dodgei, v. Eohhinsii. 

 Gynospores reticulated. 

 Plants of medium size : anfdrospores smooth . . . .11. I. Engelmanni. 

 Plants large ; androspores spinulose .... (11) 7. Engelmanni, v. ralida. 

 e. Bast-bundles 4, with accessory ones in the peripherj-. 



Monoecious; gynospores crested, somewhat reticulated (11) T. Engelmanni, y.fontana. 

 Polygamous ; gynospores smaU, smooth or with low tubercles or 



"wrinkles .12. I. melanopoda. 



§ 4. Plants of dry situations ; leaves setaceous ; bast-bundles 4 ; stomata 



many ; velum none. — Terkestres A. Br 13. 7. Butleri. 



1. I. macr6spora Dur. Leaves 10-30, 2 mm. in diameter, erect, round, dark 

 green, rather blunt ; velum covering \ of the unspotted sporangium ; gynospores 

 600-800 II in diameter, the upper faces traversed bj^ thin parallel 



walls, the lower hemisphere reticulated ; androspores 36—47 ac 

 (average 42 /x) long, smooth. — Gaspe Co., Que., and Me. to 

 Ont. and Minn. Fig. 25. 



Var. heter6spora A. A. Eaton. Leaves .50-150, 2 mm. in 

 diameter, 5-8 cm. long, rigid, erect, tapering to a sharp point; 

 sporangia spotted \-\ indusiate ; gynospores 540-075 \x (some 

 abnormally 1100-1134 /i) in diameter, densely covered with 

 thick jagged convoluted crests, often reticulated below ; andro- ^"^- ^- ^uacrospora. 

 spores 30-40 is. (average 35 ix) long, dark brown, papillose. Gynospore x lo. 

 (/. hetp.rospora A. A. Eaton.) — Jordan Pond, Mt. Desert, Me. 



2. L Tuckermani A. Br. Trunk often 3-lobed, small ; leaves 10-40, 1 mm. 

 or less in diameter, 4-15 cm. long, reddish or olive green, sometimes with a 

 few stomata but no bast-bundles ; sporangia small, rarely spotted, \ or more 

 covered by the velum ; gynospores 45U-750 /u (average 600 /u) in diameter, 

 parallel-walled or reticulated above, more or less reticulated below ; andro- 

 spores 25-38 IX (average 30 ix) long, slightly rough. — Sandy ponds, Me. to Ct. 



Var. borealis A. A. Eaton. Trunk bilobed ; leaves 10-100, 3-25 cm. long, 

 1-1.5 mm. thick, green or reddish, straight or recurved ; stomata none ; 

 gynospores 600-785 /x in diameter, more coarsely reticulated ; androspores 42 /x 

 long, finely spinulose. — N. Y. to N. H. and Lab. 



Var. Harvdyi (A. A. Eaton) Clute. Trunk 2-lobed, 1.6-3 cm. in diameter; 

 leaves 50-140, purple-bronze, 2.5-3 mm. in diameter, 5-6 cm. long, strongly re- 

 curved ; .stomata 'none ; sporangia unspotted, \~\ covered by the velum ; gyno- 

 spores 526-648 /a (average 560 ^i) in diameter ; androspores 30-39.6 /x (average 

 34 ix) long. (7. Harveyi A. A. Eaton.) —N. Y. and Mass. to Nfd. 



3. I. hieroglyphica A. A. Eaton. Leaves 10-20, 6-7.5 cm. long, 1-2 mm. in 

 diameter, blunt, recurved ; sporangia not spotted, ^ covered by the velum , 



