ISOETACEAE (QUILLWOKT FAMILY) 59 



0. Leares reddish or olive-preen. 



Gynospores averaging 440 M in diameter, with small pita . . 4. I. f&veolata. 

 Gynosporcs averaging MO M in diameter, with thin irregular 



walls (4) I./oveolata, v. pUnoipora. 



e. Leaves green d. 

 d. Oynospores with jagged crests. 



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



simple 6. 7. riparla. 



Gynospores averaging less than 550 /i i" diameter ; crests low, 



simple or reticulated. 



Leaves 1-2.5 mm. in diameter ; trunks 2-Iobed ... 6. /. naccAarata. 



Leaves 1-1.5 mm. in diameter; trunks 2-5-lobed (6) 7. succharata, v. Amenii. 



d. Gynospores with slender or jagged spines. 



Leaves short, stout, spreading I.I. echinospora. v. Brautiii. 



Leaves long, fine, spiral (7) I. ectiinotpora, v. muricata. 



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

 summer, with stomata and bast-bundles. PAL^STRES A. A. 

 Eaton e. 

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



dorsi-yentral partition f. 



f. Polygamous ; androsporaripia 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. Gratenii. 



f. Monoecious. 



Oynospores with coarse irregular crests. 



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



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

 Gynospores reticulated. 



Plants of medium size; androspores smooth . . . .11. 7. Engelmanni. 

 Plants large ; androspores spinulose . . . . (11) 7. Engelmanni, \.valida. 

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



Monoecious; gynospores crested, somewhat reticulated (11) 7. Engelmanni, \.fontana. 

 Polygamous; gynospores small, smooth or with low tubercles or 



"wrinkles ' 12. 7. melanopoda. 



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



many ; velum none. TEKKVTRES A. Br 18. 7. Butleri. 



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

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

 600-800 fj. in diameter, the upper faces traversed by thin parallel 



walls, the lower hemisphere reticulated ; androspores 36-47 /A 

 (average 42 fi~) long, smooth. Gasp6 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 $-f indusiate ; gynospores 540-675 /JL (some 

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

 thick jagged convoluted crests, often reticulated below ; andro- 2 ^- * 

 spores 30-40 n (average 35 ji) long, dark brown, papillose. G y no8 P r< 

 (7. heterospora A. A. Eaton.) Jordan Pond, Mt. Desert, Me. 



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

 or less in diameter, 4-l"> 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 450-750 /j. (average 600 /*) in diameter, 

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

 spores 25-38 /x (average 30 /i) 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 ^ in diameter, more coarsely reticulated ; androspores 42 M 

 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 M (average 560 jt) in diameter ; androspores 30-39.6 /x (average 

 34 /O long. (/. 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 bj the velum , 



