1. Lemna ecuado^cnsZA sp. nov. 
Lemnae obscurae valde affinis sed differt frondibus angustioribus (1 1/2 - 2 
partibus longioribus quan latibus) y radiadbus brevicribus .. Fructus inoogniti. 
Habitat in Ecuador. 
Type collection: Ecuador, Prov. El Oro, between Machala and Santa Rosa,.^ 
300 ft.; in a drainage ditch, leg. T. Plowman, L. Jacobs and E.W. Davis ^609; 
December 2, 1974. Holotype: U. Isotypes: F, GH. 
L. ecuadoriensis is very similar to L. obscura but its fronds are generally 
narrower, 1 V2 - 2 times as long as wide (L. obscura', 1 V5 - 1 2/3) and the 
papule at apex seems to be still more prominent; the fronds are dark red un- 
derneath and the roots relatively short (up to 1,5 cm); flowers and fruits 
are not known. 
The species is solely known from the type locality in Ecuador; it is there- 
fore difficult to decide which features are diagnostically relevant and how 
large the whole variation specter is. The taxon might be considered as a var- 
iant of L. obscura; however, the next station of L. obscura is more than 
2000 miles apart in Mexico and climatic conditions at the t 5 rpe locality are 
different from those occurring within the main distribution area of L. 
obscura. The climate at Machala (Ecuador) is warm throughout the whole year 
and shows a very pronounced dry season; on the contrary, the climate of 
Southeastern North America where L. obscura has its optimum is cool during 
winter time and has a high rainfall during the vegetation period. It seems 
reasonable to describe this collection provisionally as a separate unit. More 
material from the region is desirable. 
E. Landolt in Veroffentlichungen des Geobotanischen 
Institutes der Eidg. Techn. Hochschule Stiftung 
Rtlbei, Ztirich. vol 70: 22. 1980 , 
