14 THE TRUE GRASSES. 



is sometimes split in two parts ( Cynodori), so the palea is 

 often split at the time the fruit is mature (many Sporo- 

 bolus and Triticum monococcum L). This state has been 

 understood by some authors as originally bifoliate, and 

 false genera have been established upon it by some 

 (Diachyrium Griseb, etc.). The palea is completely 

 aborted in many Andropogonece and species of Agrostis. 



Opposite the palea, and therefore above the flower- 

 ing glume, are, in most grasses, visible two small delicate 

 scales (lodicules) ; they stand close together, their front 

 edges touching, their bases somewhat grown together and 

 swollen with sap at the time of flowering (cf. Fig. 28, f; 

 Fig. 63, G). They are usually considered the two anterior 

 members of a rudimentary perianth, whose posterior 

 member (the posterior lodicule) is developed in Stipa 

 and many Bambusece. The author has endeavored to 

 prove that the anterior scales represent the halves of a 

 leaf which sometimes (Melica, Fig. 80, jP) remains un- 

 divided, and can be regarded as a second, and the 

 posterior scale as a third, palea.* The anomalous con- 

 dition of these paleas (in respect to the ordinary palea) 

 is explained by their biological properties. The rapid 

 swelling of the bases at least, causes the separation of 

 the flowering glume and palea, and consequently the 

 opening of the flower. In grasses where they swell only 

 a little the spikelets open but slightly, and where the 

 lodicules are membranous or entirely lacking the 

 spikelets remain entirely closed at the sides, and the 

 reproductive organs protrude only at the apex (com- 

 pare Anthoxantkum, Alopecurtis, etc.). The absence of 

 the lodicules is not necessarily a case of abortion ; for if 

 they are bractlets, a decrease in their number (as in the 

 Juncacere) is not very remarkable. Their large number 

 (8 or more) and apparent spiral arrangement is striking 

 in Ochlandra ; here their relations have, however, still 

 to be studied in living material. 



All the leaf forms that have so far been mentioned 

 in the spikelet do not really belong to the flower ; 



* For details see Engler's bot. Jahrbiicher, I. Bd., S. 33. 



