A GUIDE AND KEY TO AQUATIC PLANTS 93 



8. S. cubensis Poepp. and Kunth — Introduced species, simulating 

 Cyperus, found in the southernmost part of our territory from Florida 

 westward. 



9. S. georgianus Harper — Swamps in the northern part of our terri- 

 tory. Some authorities consider it merely a variety of S. atrovirens 

 (#12). 



10. S. polyphyllus Vahl — Range similar to preceding but more 

 common. 



l\. S. sylvaticus L. — Also present only in the northern part of our 

 territory. 



12. S. atrovirens Muhl. — Another of the more northerly ranging 

 group of Scirpus. None of the preceding four has been encountered 

 often in the Coastal Plain by the writers. 



13. S. eriophorum Michx. Wool-grass — Very frequent in our 

 territory in a variety of aquatic situations. Has been found in 

 extremely acid places, in alluvial swamps, and basic artesian ponds. 

 Its close relative, S. cyperinus (L.) Kunth, with sessile instead of 

 pedicelled spikelets, may be present in the northern part of our 

 territory. Its range includes aU of our States. 



14. S. lineatus Michx. — Range includes all of our territory, should 

 ^ccur in swamps. 



15. S. divaricatus Ell. — Mostly in swamps of creeks and rivers in 

 the Coastal Plain, Florida north and west to beyond the limits of our 

 territory. 



16. S.fontinalis Harper — Known in our territory only from springy 

 pond margins in the Coastal Plain of Georgia, may occur more widely 

 for a variety of the species has recently been described from the 

 Virginia Coastal Plain. 



6. Fuirena Rottb. 



1. Leaves reduced to mere sheaths 1. F . scir-poidea. 



1. Leaves with well-developed blades 2. 



2. Plants annual, without rhizomes; perianth- 2. F.pumila. 



bristles equalling or exceeding the achene. 

 2. Plants perennial, with rhizomes; perianth- 3. 

 bristles only reaching the middle of achene or 

 shorter. 

 3. Perianth-bristles very short, not exceeding the stipe of 3. F. breviseta. 



the achene; perianth-scales orbicular or reniform. 

 3. Perianth-bristles reaching the middle of the achene; 4. F. squarrosa. 

 perianth scales deltoid-ovate 



1. F. scirpoidea Michx. — Strictly Coastal Plain in distribution, 

 Florida, South Georgia, and probably South Alabama and Mississippi. 

 A similar species, F. longa Chapm. in which the upper leaf-sheaths 

 bear leaves, occurs from West Florida to Mississippi but is not defi- 

 nitely aquatic. 



