The Flora of the Cayuga Lake Basin 45 



c. Pistillate heads or branches strictly axillary; fruit dull; beak abruptly con- 

 tracted above the dilated base; leaves 6-12 mm. wide, without a scarious 

 margin. 2. S. americanum 



c. Pistillate heads usually supra-axillary; fruit lucid; beak more gradually 

 narrowed upward ; leaves 3-9 mm. wide, with a scarious margin near the 

 base. 

 d. Fruiting heads (1) 2-4, remote or subremote, 1.5-2.7 cm. in diam., the 

 lowest 1-6.5 dm. above base of plant ; staminate part of inflorescence 2-10 

 cm. long, of 4-9 heads. 3. 6". chlorocarpum 



</. Fruiting heads 1-3, subapproximate, 1-2.2 cm. in diam., the lowest 0.1-1.8 

 dm. above base of plant; staminate part of inflorescence 1-4 (5)' cm. long, 

 of 2-5 heads. 3a. 5". c, var. acaule 



b. Fruit 3-5.5 mm. long, more ellipsoid or obovoid; beak 1.5 mm. long or wanting; 

 stipe 1 mm. long or less; stigma oblong or ovate, 0.3-0.6 mm. long; mature 

 pistillate heads 5-12 mm. in diam. ; staminate head solitary ; plant trailing or 

 floating. 4. S. minimum 



1. S. eurycarpum Engelm. Giant Bur Reed. 



In alluvial mucky soil in the larger marshes ; common. June 10-July 15. 



Spencer Lake ; Inlet Marshes ; Taughannock Point ; Cayuga Marshes ; and else- 

 where along the shores of Cayuga Lake. 



Que., N. S., and Me. to B. C, southw. to Fla., Mo., Utah, and Calif. ; less frequent 

 on the Atlantic Coastal Plain. 



2. S. americanum Nutt. (S. simplex in part, probably, and var. androcladum, of 



Cayuga Fl.) 



Marshy places, in mucky neutral or acid soils; common. June 15-July. 



Summit Marsh ; s. of Caroline Depot ; near mouth of Lick Brook ; Inlet Marshes ; 

 Dwyer Pond ; Townley Swamp ; Salmon Creek ravine ; Cayuga Marshes ; McLean 

 Bogs ; and elsewhere. 



Newf . to Minn., southw. to Fla. and Mo. ; common on the Coastal Plain. 



Specimens with branched inflorescences are sometimes separated as var. andro- 

 cladum (Engelm.) Fernald & Eames ; but the branching is of little importance, since 

 both forms, along with numerous gradations, often occur in the same colony. Fernald 

 (Rhodora 24:26. 1922) has shown that Engelmann's "androcladum" was not this 

 species and the name should not be applied to this form. 



3. S. chlorocarpum Rydb. (See Rhodora 24 : 26. 1922. S. divcrsifolium of authors. 



S. simplex, in part, of Cayuga Fl.) 



Marshy places, usually in calcareous soils ; infrequent. June-July 15. 



Summit Marsh; Inlet Marshes; Fall Creek (D. in C. U. Herb.) ; marly marsh e. 

 end of Dryden Lake ; Red Mills, and elsewhere e. of Freeville ; Spring Lake. At 

 Summit Marsh many plants were found with strictly axillary heads. 



Newf. to Iowa, southw. to Conn., n. N. J., N. Y., and Ind., including the northern 

 Coastal Plain. 



2a. S. chlorocarpum Rydb., var. acaule (Beeby) Fernald. 



In situations similar to the preceding; occasional. June- July 15. 



Marly bog at e. end of Dryden Lake. 



Newf. to N. Dak., southw. to Va. and W. Va., and on the Coastal Plain. 



Plants of low stature, but with the large heads of the typical form, occur at the 

 Cortland marl ponds. A variety of doubtful validity. 



The 5". simplex of the Cayuga Flora probably included 5". chlorocarpum and its 

 var. acaule, and unbranched S. americanum. 



