Vol. 44 T O R R E Y A January 1945 



Observations on the Distribution of some Aquatic Plants in Guatemala 



W. C. MUENSCHER 



In the preparation of a flora or catalogue of plants of a region, the aquatic 

 vegetation frequently receives the least consideration. Directly, this incomplete 

 treatment of the distribution and taxonomy of the plants growing in the hydro- 

 phytic habitat is explained by the paucity of herbarium specimens available to 

 taxonomists. Indirectly, two other factors undoubtedly contribute considerably 

 to the neglect of this group : first, the assumption that most aquatic plants being 

 rather cosmopolitan in their distribution, collections of these are, therefore, not 

 likely to yield novelties ; second, the inaccessibility of the aquatic habitat to the 

 botanical collector not provided with special equipment for collecting in the 

 water frequently results in his not attempting to take any specimens. 



During the spring of 1937, while working in Central America, I had an 

 opportunity to observe the distribution of aquatic plants in a number of ponds 

 and streams in Guatemala. In addition to these incidental observations, a day 

 was spent in a boat on each of the three larger lakes, Izabal, at tidewater, 

 Amatitlan, 4000 ft. elevation, and Atitlan, 5000 ft. elevation above sea-level. 



Assistance in the determination of plants has been received from the fol- 

 lowing: Dr. Wm. R. Maxon, Pteridophytes ; Mrs. Agnes Chase, grasses; Dr. 

 R. T. Clausen, Najas; Dr. H. K. Svensen, Eleocharis ; Dr. Paul Standley, 

 miscellaneous specimens. To these taxonomists and also to Mr. George W. 

 Perkins, Mr. E. J. LeGarde and Col. Victor E. Ruehl, who facilitated my 

 travels in Guatemala, I express my sincere thanks. The herbarium specimens 

 cited are deposited in the herbarium of Cornell University. 



Annotated List of Some Aquatic Plants of Guatemala 



^ Based upon observations and collections made by W. C. Muenscher, April 8 — May 23, 



1937) 



SALVINIACEAE 



Salviuia rotundifolia Willd. 



Floating in stagnant backwaters of streams ; also in ponds between Puerto 

 ■ Barrios and Quirigua. Rio Dulce, 12180. 

 Azolla filiculoides Lam. 



In sloughs, sluggish streams, and shallow bays in lakes. Lake Atitlan, 



12178, 12179 ; Lake Amatitlan, 12177 ; near Zacapa. 



MARSILIACEAE 



Marsilia sp. 



Sterile plants in shallow water and on sandy shore of a spring-fed pond at 

 8000 ft. elevation. Quiche, 12181. 



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