320 TRIANDRIA DIGYNIA. Ischemum. 
its anterior margins and apex enlarged with a broad, mem- 
branaceous, bifid border ; inner valve boat-shaped, keeled, ci- 
liate, and sub-aristate, one floret male, the other hermaphro- : 
dite.  Corol, glumes of each floret two-valved ; the exterior 
one of the hermaphrodite floret bifid, with a long arista in the 
fork. Calya of the pedicelled flower two-valved, two-flow- 
ered ; valvelets equal, boat-shaped, keeled, ciliate, and sub- 
aristate; one floret male, the other hermaphrodite, Coro/,as 
in the sessile flowers, and also awned in the same manner. 
_ Obs. 1am not certain that this is the original I. aristalum 
oh Lionzeus and Retzius. 
2.1. rugosum. Linn, sp. pl. ed. Willd. iv. 940. 
Erect, ramous, Leaves lanceolate; spikes paired, both 
flowers awned ; calyces oblique, obtuse, hard, and transverse- 
ly rugose, 
Is generally found growing among rice, and isso much ~ 
like it, the inflorescence excepted, that they are not, till in 
flower, to be distinguished. Leaves large, smooth ; mouths of 
the sheaths crowned with a long, two-parted ligula, , Spikes 
‘terminal, and from the exterior axills paired, erect, from two to 
three inches long. Racihis jointed. Flowers in pairs ; one ses- 
sile, the other on a short, thick, angular, clubbed pedicel. , 
Sessie Flower. Calyx two-valved ; ; vaivetets in size 
nearly equal, the exterior one tugose, and very hard ; one of 
the florets hermaphrodite, the other male, each with two 
: valves ; the i inner valve of the herr aphrodite 
flower had a long twisted awn issuing from the middle offi ite 
back. 
PrepIceLLep FLower smaller. Calyz as in the other, but 
containing two male flowers, one of which is also awned. 
sae L eS R. 
