infeiior Paka of the Grasses. 175 



the representation of the inflorescence of grasses which Robert 

 Brown (General Remarks^ p. 580) has advanced, — not, it is true, 

 as the only one possible, but as the most probable, — viz. that the 

 two leaves which have cohered to form the superior palea and the 

 inferior palea, notwithstanding the oblique direction of its in- 

 sertion, form a trimerous verticil and the outer leaf circle of a 

 perigonium, the inner circle of which is constituted by the scales 

 (lodiculse) ; but if, on the contrary, it can be proved that the infe- 

 rior and superior palese belong to two distinct axes, it is thus shown 

 that the inferior palea must be considered a bract from whose axis 

 the floral axis takes its origin ; a view which has been adopted 

 with various modifications by several authors, and which has been 

 explained in a most lucid manner by Doll (Rhein. Flora, p. 58). 

 The circumstance that a diff'erence of opinion has prevailed on 

 this fundamental point in the morphological consideration of the 

 inflorescence of the Graminece, undoubtedly proves that the exa- 

 mination of the normal flowers of grasses does not afford suf- 

 ficiently certain and convincing proofs to decide with positive 

 certainty the question respecting the derivation of the palese ; it 

 appears, therefore, to be safest in this case, as in so many other 

 morphological questions, to look out for monstrosities from which 

 we may be able to deduce the normal structure ; and if I am not 

 very much deceived, the variety vivipara of Poa alpina, so widely 

 diff'used in the Alps, is fully adapted to solve the doubt existing 

 on the above question. I trust, therefore, that a description of 

 this monstrosity, drawn up with reference to the morphological 

 relations of the spicula of grasses, will not be without interest. 



In the viviparous spikes of the Poa alpina I have found the 

 two calycine valves (PI. XIII. B, fig. 1 to 4 c c) always perfectly 

 normal, and only the palese deformed; the deviation from the 

 normal structure is generally less in the most inferior flower than 

 in the succeeding one, so that frequently the lowest is still per- 

 fectly normal (fig. 3), or approaches more to the normal structure 

 than the flower situated higher up (fig. 4) . 



The axis of the spicula exhibits the least variations. It is, as 

 far as it bears abnormal flowers, more or less thickened, full of 

 sap, presents an unlimited growth superiorly, and frequently 

 small rootlets shoot out from its inferior internodes ; in short, it 

 has assumed the characters of an axis of vegetation, and perfectly 

 resembles with its leaves a small culm of grass (PI. XIII. fig. 1) ; 

 while its inferior portion, which bears the calycine valves and 

 forms the petiole of the spicula, is of the same small diameter as 

 in the normal spicula, and, like the fruit-bearing spicula, dries 

 up after the flowering season, which admits of the falling off" and 

 independent vegetation of the upper deformed portion. 



In the monstrous flowers the inferior palea presents an increase 



