recently discovered in Scotland by Mr. George Don. 335 
is perhaps the only mode with respect to grasses. "This is by an 
absolute transmutation, more or less complete, of the glumes of 
the corolla into leaves. That such is the case, is evident, not 
only from the change being mostly incomplete, part of the glume 
retaining its natural state, but also from the awn terminating the 
newly-formed leaf. Indeed it often seems as if the iower part 
only of the awn itself had become leaf, the glume which bears 
it remaining unchanged. "The gay petals of a tulip often become 
in part or entirely leaves. Why may not this happen to a grass ? 
It seems that the organs of impregnation are starved and obli- 
terated in such viviparous florets of this Aira, and not as some 
have supposed concerning other alpine viviparous grasses, that 
those parts are themselves transformed into a gemma, orleaf-bud ; 
still less is the leafy appearance caused by the seeds vegetating 
in their husks, as Lightfoot thought of Poa alpina, and perhaps 
Festuca vivipara. |t is possible indeed that the stamens, and 
even pistil, of all such grasses may be capable of change into 
leaves, as well as the corolla, though I have not found it so in 
this Aira. | 
2. AvENA alpina*, 
paniculä ui subsimplici, calycibus subquinquefloris, recep- 
taculis apice barbatis, foliis serrulatis nudis ; vaginis scabris. 
Discovered in 1807, on rocks upon the summits of the highest 
entans of Clova, Angusshire. Itis perennial, flowering in June. 
- This is a very fine species of Avena, and, as far as I can discover, 
perfectly new. I was inclined to refer it to pubescens, with which 
it most agrees in general aspect, but is larger in every part, and 
| * Avena DRE Engl. Bot. t. 2141, and as I presume of Schrader’s: Fl, Germ. 
v. 1. 381. f. 6. f. 2; but Mr G. Don thinks otherwise, and denies the flatness of the 
stem in his plant. 
. 2x2 Mr. 
