404 



SYSTEMATIC BOTANY. 



Tribe 3. POACE^E. Spikekts 

 visually articulated above the lowest 

 glume, 1- or many -flowered ; lowest 

 flower usually perfect, terminal flower 

 very rarely more perfect than those 

 below it ; axis of the spikelet almost 

 invariably terminated by an imper- 

 fect glume, which is frequently re- 

 duced to a small point or bristle ; 

 Iodides generally 2, sometimes 3 ; 

 stamens 1-3, rarely 6 ; fruit al- 



ways shorter than the flowering 

 glume. 



Agrostis, L. 



Stipa, L. 



Oryza, L. 



A vena, L. 



Festuca, L. 



Bromus, L. 



Bambusa, L. 



Hordeum, L. 



Triticimi, L. 



Affinities, &c. The tribes above mentioned are those adopted by General 

 Monro, the leading authority on this immense and difficult family. The 

 description of the Grass-inflorescence above given is in accordance with 

 the most modern views of botanists. According to this interpretation, 

 the outer and inner glumes are involucral bracts common to all the flowers 

 of the spikelet, the outer palea or flowering glume is a bract in the axil of 

 which the short axis bearing the flower springs. This short axis bears the 

 inner palea or " Vorblatt, 1 ' consisting perhaps of two bracteoles united 

 together. The perianth consists of two Iodides placed collaterally, . . ; 

 the androecium is made up of 3 stamens, the odd one anterior, v ; the 

 gynaecium of two carpels. The entire flower, omitting the bracts and 

 bracteoles, may therefore be thus represented, P . . Av G . To harmonize 

 this arrangement with that typical of Monocotyledons, viz. P *.+.'. Av + 

 .*. G v, it must be assumed that three outer parts of the perianth, one 

 (posterior) part of the inner perianthial row, three stamens of the inner 

 row, and one (anterior) carpel are suppressed. Now in Streptochwta spi- 

 cata, according to Doll, the ordinarily missing parts are present, and the 

 Monocotyledonous symmetry is restored, its floral formula being identical 

 with that just given. In Bamboos and in Stipa the third lodicle (pos- 

 terior) is present. In diandrous Grasses (Anthoxanthuni) the outer stamen 

 is wanting ; in most Grasses the inner petal (lodicula) is absent. The 

 inner (double) pale is absent in Alopecurus, Panicum, &c. ; in Lolium and 

 Lepturus the outer glume is absent ; in addition to which the few-flowered 

 spikelets of very many genera contain abortive, unisexual, or neutral 

 florets, consisting of rudimentary pales. The comparison of the typical 

 floral structure of Monocotyledons, P3-f3 A 3+3 G~3, with that of 

 Grasses in general may be indicated by placing the numbers referring to the 



suppressed organs in italics, thus : P +^ +A 3+3 G~3. By Robert 



Brown and many others, the flowering glume and the inner palea were 

 looked on as constituting three sepals of a calyx ; but the outer palea or 

 flowering glume belongs to a different axis, is inserted lower down, and 

 encircles the floral axis at the base, and the inner palea is a bracteole. 



Link looked upon the lodiculce as analogous to the scales in the throat 

 of Narcissus, therefore apparently as representing the ligules of metamor- 

 phosed Grass-leaves. The remarkable awn which is produced on the 

 flowering glume of many Grasses, more or less free from its lamina, is 

 regarded by some authors as a barren development of the axis of the 

 spikelet, which would make the inner pale the subtending bract of the 



