224 



MEMOIRS OF THE NEW YORK BOTANICAL GARDEN (Vol. 9, No. 2 



obovate, 2.3-3.2 x 1.6-2.3 mm, the faces 0-2-winged, the obliquely inserted beak 

 (0.7-) 1-1.5 cm long, strongly recurved. (FIG. I8d, e.) 



Type collection: 1832, Drummond s.n., Alabama (holotype, not seen, K; frag- 

 ment of holotype MO). Judging from the fragment, the holotype is juvenile but 

 characteristic. 



Distribution: New York to Indiana, south to the Gulf States; common, especially 

 in the Appalachian Mountains, in lakes, ponds, and swamps, rarely in acid water. 

 Collections examined from Alabama, Delaware, Georgia, Indiana, Kentucky, Mary- 

 land, Mississippi, New Jersey, New York, North Carolina, Ohio, Pennsylvania, 

 South Carolina, Tennessee, Virginia, West Virginia. (FIG. 18.) 



17c. Sagittaria engelmanniana subsp. brevirostra (Mack. & Bush) Bogin, comb, 

 nov. 



Sagittaria brevirostra Mack. & Bush, Missouri Bot. Gard. Rep. 16: 102. 1905. 



Leaves sagittate, with mostly lanceolate blades 5-20 x 2-8 cm, the basal 

 lobes linear to lanceolate. Scapes branched, with 5-12 whorls of flowers. Bracts 

 firm, 1-3 cm long or longer. Pedicels 1.3-2.5 cm long. Receptacle 1.5-2.5 cm 

 thick; achenes cuneate-obovate, 2.3-2.7 x 1.6-1.9. mm, the faces 0-1-winged, the 

 ascending apically inserted beak 0.5-1 mm long. (FIG. 18 f, g.) 



Type collection: Bush 1917, Courtney, Jackson Co., Missouri (lectotype MO; 

 isolectotype GH, US). Mackenzie and Bush cited Bush 1917 and 2275 in their 

 original description of 5. brevirostra. The lectotype is the more characteristic and 

 is better represented in herbaria. 



Distribution: Ohio and Michigan, west to South Dakota, south, west of the 

 Mississippi, to Texas; in sloughs, swamps, and ponds. Collections examined from 

 Arkansas, Indiana, Illinois, Iowa, Kansas, Michigan, Missouri, Nebraska, Ohio, 

 Oklahoma, South Dakota, Texas. (FIG. 18.) 



An interesting member of the subgenus Sagittaria with typically sagittate leaves 

 and glabrous filaments, S. engelmanniana is closely related to 5. latifolia and 

 5. cuneata. It probably hybridizes with both of these species to some extent. At 

 one time the entire species was included in the catch-all Sagittaria variabilis 

 Engelm. In the last 50 years, however, three species have been proposed and 

 maintained by most authors. These are not maintained here because of their specific 

 similarities in all key characteristics and the numerous intermediates that have 

 been collected. Reducing them to a subspecific level is justified since the extremes 

 of each population are quite distinct and each has a correlated geographic and 

 ecological distribution. 



'Mie subspecies engelmanniana is limited to bogs and acid waters along the 

 Atlantic coastal plain. Typically it has linear leaves that are sagittate or lobeless 

 (possibly an ecological response to high acidity), membranous bracts, echinate 

 receptacles, and a few-whorled scape. Vegetatively, it resembles S. latifolia in 

 the same habitats to a remarkable degree. Some intermediates between these two 

 have been seen, suggesting hybridization. It is commonly found associated with 

 S. graminea var. teres. A completely intergradating series between subsp. 

 engelmanniana and subsp. longirostra is demonstrated by Godfrey & Try on 1477 

 and 1477V2, both of which represent a single collection. 



The subspecies longirostra, with its broadly sagittate leaves, strongly re curved- 

 beaked achenes, and bracts equaling or exceeding the pedicels, replaces subsp. 

 engelmanniana inland and southward. However, in portions of the coastal plain, 

 swarms of intermediates can only hesitantly be separated. Several collections of 

 plants from the Finger Lake district of New York, closely resembling subsp. 



