Echinodorus (Burhead) 



Plants of sandy shores, often spreading by creeping shoots; leaves 

 basal, submersed leaves lance-linear phyllodia; emersed leaves petio- 

 late with a lanceolate blade; flowers perfect in an umbel; fruit an 

 achene. 



1. Echinodorus parvulus Engelmann Fig. 3, Map 4 



A plant of sandy shores which has been reported from four sites in 

 eastern Massachusetts, but now believed extinct in our region. The last 

 known locality was Winter Pond, Winchester, Massachusetts. The 

 pond has been treated with herbicides on several occasions and the 

 species has not been reported there since 1970. 



The taxon is treated by some authors as Echinodorus tenellus 

 (Mart.) Buchenau var. parvulus (Engelmann) Fassett. Populations 

 apparently occur locally. Range extends from Massachusetts west to 

 Ontario and Minnesota, south to central Florida and southern Texas. 



Rare and endangered plant lists: Massachusetts, New England 



Sagittaria (Arrowhead, Wapato, Duck-potato) 



Plants of fresh or saline waters; growing in marshes, ditches, pond 

 shores, lakes, streams, and estuaries; emergent or submersed; growing 

 from fibrous septate roots; spreading by stolons, some of which pro- 

 duce tubers. Leaves extremely variable, blades sagittate or hastate to 

 lanceolate, or bladeless, phyllodial, ribbon-like to subulate, submersed, 

 floating or erect; flowers white, whorled in three's; bracts membran- 

 ous; uppermost flowers usually staminate; fruit an achene. 



Key to Species 



1. Sepals of mature flowers appressed (fig. 4D); pedicels thick and 

 spongy (fig. 4A); leaves erect, spongy (fig. 4A); tidal mudflats. 



1. S. montevidensis ssp. spongiosus 



1. Sepals of mature flowers reflexed (fig. 5B); pedicels more slender, not 

 spongy; leaves erect or lax, not spongy; mostly freshwater. 

 2. Leaves narrow linear phyllodia, 1-3 mm wide (fig. 5A, 6A), occa- 

 sionally with floating ends broadening into a narrow blade (fig. 

 6A). 



3. Plants small with linear leaves up to 30 cm long (fig. 5A); 

 mostly estuarine. 

 2a. S. subulata var. subulata 



