62 GRASSES OF SCOTLAND. 



Calyx of two membranous smooth acute glumes (Fig 1), nearly of 

 equal lengths; the outer glume the smaller, seven-ribbed; the inner 

 glume eleven-ribbed. Florets of two paleae, (Fig. 2), the outer palea 

 of lowermost floret ovate, acute, much shorter than the calyx, eight- 

 ribbed, furnished with several long reddish-brown hairs, with their 

 points directed upwards. Inner -palea shorter than the outer pa- 

 lea, membranous, with two green marginal ribs minutely fringed. 

 Awn more than twice the length of the floret, of a reddish-brown, 

 twisted and bent, arising a little beneath the centre of the outer palea. 

 Seeds hairy. 



Ohs. — Avena fatua is distinguished from Avena strigosa in the 

 florets being much shorter than the calyx ; outer palea with four 

 ribs on each side ; the summit acute, but not awned ; — whereas in 

 A. strigosa the florets are equal in length to the calyx ; outer palea 

 with only three ribs on each side ; the summit terminating in two 

 acute stout bristles. 



From Avena sativa, (common cultivated oat), in the spikelets being 

 much larger ; outer palea very hairy, with four ribs on each side ; 

 — whereas in A. sativa the outer palea is not hairy, and there are but 

 three ribs on each side. 



This grass is generally found in corn-fields, especially among bar- 

 ley, where it proves a troublesome weed. It is occasionally met with 

 in Scotland, but more frequent in England and Ireland. It occurs 

 in Lapland, Norway, Sweden, Germany, France, Italy, Asia, and 

 North Africa. Not found in America. 



Flowers in the first week in July, and ripens its seed about the end 

 of August. Its limit of altitude seems to be about 1000 feet above 

 the sea. 



The florets, on account of their somewhat resemblance to artificial 

 flies, are occasionally used by rustic fishermen to catch trout, and of- 

 ten with success. 



The awns make excellent hygrometers, being very sensitive to the 

 humidity of the atmosphere, which causes them to expand, and during 

 dry weather they contract. 



