ISOETACEAE 



67 



11. L. carolinianum L. In moist pine-barrens, N. J. to Fla. and 

 La. near the coast. 



N. J. Common in the pine-barrens, rare along the coast and at 

 Cape May.* 



SELAGINELLACEAE 

 1. Selaginella Beauv. 



Stem-leaves all alike, many-ranked. I. 5. rupestris. 



Stem-leaves of two kinds, 4-ranked, spreading in 2 planes. 2. 5. apus. 



1. S. rupestris (L.) Spring. On dry rocks: N. Eng. and Ont. 



to Ga. and the middle West. 



Scattered throughout the range, except the N. J. coastal plain 

 and L. I., there not recorded. 



2. S. apus (L.) Spring. In moist open places, often among grass: 



Me. and Ont. to the N. W. Terr., south to Fla., La. and Tex. 

 Throughout the range, except the pine-barrens. 



ISOETACEAE 

 1. Isoetes L. 



Sporangium spotted with sharply defined brown or lighter cells. 



Macrospores somewhat flattened on one hemisphere, averaging 

 less than 450 /j. in diameter. 

 Spots of sporangium scattered, mostly i-few-celled; macro- 

 spores covered beneath with thick-walled reticulations, 

 the openings resembling small pits, and between the 

 commissures with more open reticulations. 

 Sporangium densely brown-spotted; macrospores densely 

 covered with low simple truncate columns or labyrinthi- 

 form convolute ridges on both. 

 Macrospores not flattened, averaging more than 475 11 in 

 diameter. 

 Spots of sporangium scattered, many 1- or 2-celled; 

 stomata and peripheral bast-bundles absent;! macro- 

 spores covered beneath with an irregular network, and 

 between the commissures with wavy, somewhat parallel 

 or branching, wall-like ridges. 

 Spots of sporangium mostly several-many-celled; stomata 

 present. 

 Peripheral bast-bundles sometimes present, some- 

 times absent; sporangium pale-spotted; macrospores 



* See Introduction paragraph 29. 



t It is doubtful if the presence or absence of stomata or peripheral bast-bundles is 

 more than a variable character in many species of Isoetes. This genus is in needof care- 

 ful revision. M.S. 



6. I. foveolata. 



8. I. Eatoni. 



2. I. Tuckermani. 



