H(3RTUS GRAMINEUS WOBURN ENSIS. 231 



when the seed is perfected ; calyx-valves equal, the 

 outer only serrulated, larger valve of the corolla with a 

 minute straight awn fixed above its middle, and reaching 

 to its point, obsolete. 

 Experiments. — At the time of flowering, the produce from 

 a bog soil is 10,209 lbs. per acre. 



This grass is properly a subaquatic. It will grow on 

 tenacious clays, but it seems only to thrive in very moist 

 soils, or in such as are for the most part covered with water. 

 In moist woods it is more frequent than any other of the 

 creeping- stemmed bent grasses ; here the culms often attain 

 to five feet in height, when supported by bushes. 



The above details show the inferior nature of this grass, 

 compared to the larger, and even to the lesser-leaved varie- 

 ties of tlie agrostis stolotn/era. It cannot, therefore, as yet 

 be considered in any otlier light than a weed that chokes up 

 drains and underwood. 



Flowers about the second week of July, and the seed 

 is ripe about the middle and towards the end of August. 



GLYCERI A. — Generic character : Corolla awnless, cylin- 

 drical furrowed, ribbed abrupt, not keeled : seed loose,, 

 cylindrical oblong. 



G/j/ceria jluitans. Floating Sweet-grass. 



Specific character: Panicle oblong, branched, divari- 

 cating; spikelets close pressed ; florets numerous, obtuse^ 

 seven-ribbed, with short intermediate ribs at the base ; 

 nectary obtuse, tumid. 



Obs. — This grass has sometimes been mistaken for the 

 agrostis stolouifera (florin). When in flower there is no 

 difficulty in distinguishing them, the number of florets 

 in each calyx being from five to eleven ; in florin only 

 one. The leaves are much broader, flat, and perfectly 

 smooth. By simply drawing the finger down the 

 leaves of the fiorin they will be found sensibly rough 

 to the feel, but those of the floating sweet-grass perfectly 

 smooth ; by which means the two grasses may be 

 distinguished at any stage of growth. 



