368 



to find it noticed in the continental works, he proposed for it the 

 name of Biaristatus, as illustrative of the species. Several specimens 

 gathered in the neighbourhood of Edinburgh were exhibited, and the 

 characters by which it differed from Holcus mollis and Holcus lana- 

 tus were pointed out. 



Specific Characters. — Both florets awned ; sheaths of leaves 

 smooth ; joints slightly hairy. (See Plate I.) 



Description. — The Holcus biaristatus grows to the height of two 

 feet or more, but more frequently of about eighteen inches. The 

 root is perennial, fibrous, somewhat creeping. The stem round, 

 smooth, and striated, bearing four or five leaves with smooth sheaths ; 

 the upper sheath crowned with a prominent obtuse ligule. Joints 

 five in number, furnished with a few delicate haii's with their points 

 directed downwards. Leaves flat, broadish, acute, of a light green 

 with whitish rough margins, both surfaces soft and slightly rough- 

 ish to the touch. Injloreseence mostly simple panicled. Panicle 

 erect, the rachis and branches hairy. Spikelets pendulous, rather 

 large and few. Calyx of two glumes nearly of equal lengths, mem- 

 branous, acute, hairy at the keels ; lower glume the smaller ; upper 

 glume with a prominent green rib on each side. Florets two, 

 both awned, of two palese, the outer palea of the lowermost floret 

 about the same length as the small glume, pedunculated, of a lan- 

 ceolate ovate form, smooth and glossy, with two delicate lines or ribs 

 on each side ; keel slightly hairy towards the upper half, the base 

 furnished with a few slender white hairs ; the upper or inner palea 

 membranous, about equal in length to the outer palea, and minutely 

 fringed at the margms. The upper floret sometimes wanting, but 

 when present of about the same size and appearance as the one be- 

 low, and elevated on a smooth peduncle about one-third the length 

 of the floret. Awn rough, arising from a little beneath the apex 

 of the outer palea, about equal in length to the palea, mostly straight, 

 and projecting conspicuously beyond the calyx. 



Holcus biaristatus differs from Holcus mollis and Holcus lanatus in 

 the followmg respects : — In Holms mollis (see Plate I.) the lower- 

 most floret is of an ovate form, about half the length of the small 

 glume, without a long dorsal awn or lateral ribs, whereas in Holcus 

 biaristatus the lowermost floret is ovato lanceolate, about equal in 

 lencrth to the small glume, furnished with a long dorsal awn, and the 

 sides with two lines or ribs. 



In Holcus lanatus (see Plate II.) the lowermost floret has no dor- 

 sal awn, the uppermost floret with a short curved, smooth awn, 



