THIHKS AM) snn'IMUF.S. 7 



be roganlc'cl sis two or three bractlets inserted cilti'rnutcly fore and 

 aft on the Horal axis below the flo ,er. The only representations of 

 li()niolo<;iies to the pak-a and lodienles in the orders nearly allied 

 to (Jraniinejt are mentioned in niy paper (Journ. Linn. Soe. (Hot.), 

 XV. J). 510), where it is eonipared with the hypogynous scales of 

 J/i/^ti)li//niiii pungens and I'l((fi//i'pi^, and some species of L'n'i)- 

 caiduit. 



"In all cases the palea . . . acquires a certain fixity of char- 

 acter, and requires mention in all full generic characters, 'i'he 

 lodicules. on the other hand, are generally rudimentary representa- 

 tives of suppressed organs having lost all functional powers [*|, 

 . . . and their slight variations in form or consistency are generally 

 not even of s[tecilic importance.'' 



^'ear the end of this volume will be found a [lartial list of works 

 on Gramineffi, with comments concerning a few of them. 



THE DIVISION INTO THIHES AND SI HTIUHES. 



"The division of the order into tribes mid subtribes is a matter 

 of exceptional ditliculty. Whatever tribes have been ]>roposed, 

 whatever characters have been assigned to them, tiiere have always 

 been more or less Jimbiguous forms uniting them and preventing 

 the restricting them within absolutely definite limits. We are 

 obliged in fJraminea?, more perhaps than in any other order, to 

 rely upon combinations of characters, allowing for occasional 

 exceptions in every one of our groups, [(referring those which 

 exi)erience has shown to jtreaent the fewest aberrations. Following 

 up these views, none of the general divisions of the order 

 hitherto proj)osed have proved to be more natural or more definite 

 than Jirown's original jjrimary one into two great groups or sub- 

 orders — Pdiifrarece, in which the tendency to imperfection is in 

 the lower fiowers of the s{)ikelet; and Piuiira'. in wliicli the ten- 

 dency is in the opposite direction. This indication of the principle 



* Tlifi use of lodicules is to sprf-ad tlip ulinncs and pnlca wlu'ti the plants 

 are in Hower. At such times tbuv are turgestent, liut soon alter witlier. 



