Ix] “SEEDS ” 141 
3—5 nerved and with a faint web. It is close to 
P. pratensis. 
Poa trimalis, L. (Fig. 56). 
“Seed” 2—2°5 mm., and with a bluish or bronzed 
cast. Caryopsis 1—1°5 mm. 
Palea acute, distinctly five-ribbed, glabrous, the margin 
scarcely overlapping. Caryopsis grooved, blunt and more 
tightly held in the palea. 
P. trivialis differs from P. pratensis chiefly in the distinct ribs 
and smoother palea, grooved caryopsis, and bluer hue. 
P. nemoralis, L., hardly differs from P. trivialis, but 
the palez are sub-acute, nerves obsolete, and scarcely 
hyaline at the margins. The “seed” is shorter and more 
acute, and the colour less pronounced, and with hardly a 
trace of hairs (Fig. 54). 
When the basal hairs are absent this should go with 
P. annua, &e. (see p. 146). 
It is practically impossible to distinguish these species by the 
“seed.” Care is necessary to distinguish A @/eria, which is somewhat 
larger in size, keeled, compressed and nerved similarly, but is more 
pointed and curved and paler yellowish white in colour. Hard and 
devoid of web or hairs. A?ra is distinguished by the awn: Agrostis 
by the very different paleze and caryopsis. 
The other Poas are devoid of web, though they may have hairs 
below, and require very careful examination. The whole group is 
excessively difficult to deal with in “seed,” and a special study of it 
is needed, since several species are important, and it forms a type. 
(b) No web or pencil of hairs below the “seed.” 
(1) Apex of palea rounded, blunt, notched, or at 
most bluntly pointed, but with no trace of 
awn- or bristle-tip. 
