318 Karl M. Wiegand and Arthur J. Eames 



95. HALORAGIDACEAE (Water Milfoil Family) 



a. Leaves whorled. 



b. Leaves pinnately dissected; stamens 4-8; fruit 4-celled, 4-lobed. 



1. Mykiophyllum 



b. Leaves entire, linear ; stamen 1 ; fruit 1-celled. 2. Hippuris 



a. Leaves alternate; stamens 3; fruit 3-celled, 3-angled. 3. Pkoserpinaca 



1. Myriophyllum (Vaill.) L. 



a. Bracts entire or denticulate. 



b. Bracts oval, not longer than the fruit ; stamens 8 ; fruiting carpels 2-3 mm. 

 long, smooth ; stigmas obscure ; rhachis of leaf about the width of the divisions. 



1. M. exalbcscens 



b. Bracts oblanceolate, much longer than the fruit ; stamens 4 ; fruiting carpels 



1-1.5 mm. long, papillose, 2-ridged on the back; stigmas prominent; rhachis 



of leaf slightly broader than the divisions. 2. M. heterophyllum 



a. Bracts pinnatifid or pectinate ; stamens 8 ; fruiting carpels 2.5-3 mm. long, smooth ; 



stigmas prominent, recurved ; rhachis of leaf slightly broader than the divisions. 



3. M. verticillatum, 

 var. pectination 



1. M. exalbescens Fernald. (See Rhodora 21: 120. 1919. M. spicatum of authors 



and of Cayuga Fl.) Water Milfoil. 



Waters of the larger lakes and their adjacent marshes; frequent. July-Aug. 



"Common in the Inlet of Cayuga L., the mouth of Fall Cr., and throughout the 

 lake and outlet in shallow water, to Montezuma" (D.\) ; head of Cayuga Lake; pool 

 on Taughannock Point ; Cayuga Marshes. 



Lab. to Alaska, southw. to Conn., N. Y., the Great Lakes, Kans., N. Mex., Ariz., 

 and Calif. Found also in Eurasia. A northern species. 



Perhaps influenced in its local distribution by the slightly brackish character of the 

 Cayuga Lake waters. 



2. M. heterophyllum Michx. 



In calcareous and slightly brackish waters ; rare. Aug.-Oct. 



"Outlet of North Spring at Union Springs" (D., a specimen in C. U. Herb.) ; not 

 seen by the authors. 



N. T. to Fla., near the coast ; also from cent. N. Y. and Ont. to Minn., southw. to 

 Mo. and Tex. 



3. M. verticillatum L., var. pectinatum Wallr. (M. verticillatum of Cayuga Fl.) 

 Waters of the larger lakes and their adjoining marshes; rare. Aug. 



"Bayou near mouth of Fall Cr. (Trelease, 1878)!" (D.) ; s. end of Cayuga 

 Lake (D.) ; Montezuma Marshes, in the pits near the marl works (D.) ; Cayuga 

 Bridge, 1874 (D.) ; "occasional in the lake-outlet" (D.). Not seen in recent years. 

 Dudley specimens from the Fall Creek, s. end of Cayuga Lake, and Montezuma sta- 

 tions are in the C. U. Herb., and a Dudley specimen from the Fall Creek station is 

 in the Gray Herb. 



Newf . and Ont. to Wash., southw. to Md., 111., and Utah ; rare or absent on the 

 Atlantic Coastal Plain. 



2. Hippuris L. 

 1. H. vulgaris L. Mare's-Tail. 



" 'Cayuga, Dr. Jed. Smith,' (Sartwell in H. and C.) Not uncommon about 

 the outlet of North Pond at Union Springs 40 or 50 years since. (Prof'r J. J. 

 Thomas.)" (D.) ; not seen by Dudley or by the authors. 



Lab. to Alaska, southw. to N. S., Me., Vt., N. Y., Ind., 111., Nebr., N. Mex., and 

 Calif., especially in calcareous and saline situations. Found also in Eurasia and S. A. 



