GRASSES OP IOWA. 49 



close together. Various views have been held in regard to these 

 lodicules. The question has been discussed by Bentham, who 

 states: " It might therefore be suggested that the palea and 

 lodicules of Graminese represent perianth-segments of an 

 outer and inner series, although -I by no means pretend to 

 assert it as a proved fact." Hackel* in an early paper dis- 

 cussed the original homology of these organs. In his own 

 words in a later paper, "The author has endeavored to prove 

 that the anterior scales represent the halves of a leaf which 

 sometimes (Melica, Fig. 81, f.) remains undivided, and can be 

 regarded as a second, and the posterior^ scale as a third, palea. 

 The anomalous condition 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 open- 

 ing of the flower. In grasses where they swell only a little 

 the s pikelets open but slightly, and where the lodicules are 

 membranous or entirely lacking, the spikelet remains entirely 

 closed at the sides, ard the reproductive organ protrudes ocly 

 at the apex (compare Anthoxanthum, Alopecurus, 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 

 Juncacese) is not very remarkable. Their large number 

 (eight or more) and apparent spiral arrangement is striking in 

 Ochlandra; here their relations have, however, still to be 

 studied in living material. " 



The subject of lodicules again finds discussion in a recent 

 paper by W. W. Rowlee. f 



Arrangement of thefloioers. — The arrangement of the spikelets 

 upoi the stem constitutes what is termed the inflorescence, or 

 what we often hear erroneously called the "head." If that 

 portion of the main, axis -^r stem which bears the spikelets is 

 unbranched so that these are sessile (?. e., without pedicels), 

 the inflorescence is a spike, as in wheat or rye grass: when 

 the main axis is branched, each branch forming a pedicel to a 

 single spikelet, the inflorescence is a raceme. This form is 

 not common. Usually the primary branches branch again and 

 again, resulting in the formation of a panicle. The panicle 

 may be open or widely spreading, as in oats or in Kentucky 

 blue-grass; or, if the branches are very short, it may be narrow 



*Eagler's bot. Jahrbuecher. 1:33. 

 The morphological significance of grasses. Bot. Gaz 25:199. 



