A GUIDE AND KEY TO AQUATIC PLANTS 83 



2. Glume almost as long as the lemma 1. P. gymnocarpon. 



2. Glume much shorter than lemma 2. P. hemitomum. 



3. Plants with conspicuous creeping rhizomes 3. P. virgatum. 



3. Plants without creeping rhizomes 4. 



4. Panicles narrow and few-flowered 4. P. tenerum. 



4. Panicles more or less spreading 5. 



5. Spikelets 1.8 to 2 mm. long; panicle branches ascend- 5. P. agrostoides. 



ing or spreading. 



5. Spikelets 2.5 mm. long; panicle branches erect or 6. P. condensum. 

 nearly so. 



1. F. gymnocarpon Ell. — Lower Gulf State species, Georgia and 

 Florida westward, usually associated with rivers or streams. 



2. P. hemitomum Schultes. Maideucane — Coastal Plain species, 

 ranges over all of our Coastal Plain territory. Makes good growth 

 in open, grassy limesinks and occurs also in the Okefinokee Swamp. 

 It is perhaps the most important of the aquatic Panic-grasses. 



3. P. virgatum L. Switchgrass — Aquatic and other situations 

 mostly along the coast, but range includes most of our atea. 



4. P. tenerum Beyr. — Coastal Plain, North Carolina to Florida and 

 Texas, seems to prefer acid situations. 



5. P. agrostoides Spreng. — ^Well distributed over our area, in some 

 places {\n important constituent of the aquatic flora, usually occupies 

 a marginal position. 



6. P. condensum Nash — Resembles the preceding, but of Coastal 

 Plain distribution. In addition to the six given, there are several 

 other Panic-grasses which sometimes appear to be aquatic, and there 

 are in South Florida perhaps two truly aquatic species which are not 



listed. 



11. Sacciolepis Nash 



S. striata (L.) Nash — Frequent in portions of our region, in Georgia 

 seems to prefer acid situations, range includes all of our Coastal 



Plain. 



12. Echinochloa Beauv. 



I. Lower leaf-sheaths smooth; awns various but panicles 1. E. crusgalli. 



not densely hairy. 

 I. Lower leaf-sheaths hairy; panicles densely hairy from 2. E. ivaUeri. 



long-awned spikelets. 



1. E. crusgalli (L.) Beauv. Wild Millet — Widely distributed, often 

 weedy, range includes all of our area, it and the following species 

 common near the coast. 



2. E. walteti (Pursh) Heller — In marshes along the coast, less 

 commonly in aquatic areas near the larger rivers, range includes all 

 of our territory. 



