46 



AiRA pRjECOX. Early Hair Grass. Plate XL. 



Panicle compact^ often spicate. Spikelets two-flowered. Awn 

 from below the middle or near the base of the outer palea, extend- 

 ing beyond its bifid apex. Leaves short, narrow; their sheaths 

 smooth. 



Aira prsecox, Linneeus. E. B. 1296; ed. 2. 108. Generally 

 adopted by British botanists. Avena, Koch. 



Very frequent on sandy heaths and commons and by road- 

 sides. The stemSj from one to five or six inches high, rise erect, 

 usually several from the same root amidst a tuft of small, almost 

 setaceous leaves. Panicle of few branches, and, even in larger 

 specimens, scarcely expanding as such ; while in those of average 

 and smaller size, the spikelets are nearly sessile, giving the in- 

 florescence the character of an oval or oblong spike, varying 

 from half an inch or less to an inch in length : the colour when in 

 flower is a pale greenish-grey. The glumes are ovate-lanceolate, 

 but less inflated or turgid at the base than those of A. caryophyllea ; 

 hence the spikelets are less rounded below than in the latter species. 

 The length and insertion of the awn are variable, but it is always 

 extended considerably beyond the bifid extremity of the palea. 

 No rudiment of a third flower is traceable. 



Annual. Flowers in April and May. 



It is difficult to frame a specific character of distinction between 

 this and the preceding species, except from the compactness of the 

 panicle and comparatively larger size of the spikelets in the present. 

 Their general appearance is, however, so very dissimilar, as to 

 render mistake by the most superficial observer next to impossible. 

 Our figures express the peculiarity of habit, laxity in the one and 

 rigidity in the other; and though in small specimens of A. caryo- 

 phyllea these features are less exaggerated, they will still be found, 

 on comparison, sufficiently expressive to keep apart two plants, 

 which, with many common characteristics, have no real affinity 

 beyond association in the same genus. 



It will be observed, by reference to the sectional arrangement 

 and synonyms of the five British species of Aira above described, 

 that they have been regarded by diiferent botanists as involving 

 types of three distinct genera, Deschampsia, Aira, and Airopsis. 

 In a local monograph, like that before us, such a division, founded 

 between the first two upon very equivocal features, and not gene- 

 rally adopted in either instance, has been avoided as unnecessary 

 to accuracy of description, and tending to. complicate the subject. 

 But the attention of every practical botanist must be arrested by 

 the fact, that the two species, composing our second division, are 



