14 STRUCTURE 
the outermost consists of two lodicules placed at the anterior side 
of the flower, z.e. furthest from the axis or rachilla, the posterior 
lodicule being aborted or suppressed; three stamens constitute the 
middle whorl, while the innermost whorl consists of two carpellary 
leaves united into a single-celled ovary, which still retains two 
styles and stigmas. Suppression of the anterior stamen may occur, 
as in Anthoranthum odoratum and some of the Bromes ; some- 
times the two posterior stamens are suppressed, as in Festuca 
a 
Fic. 11.—Diagrams of grass-flowers showing symmetry. Explanation of symbols: 
outside dot represents the axis (rachilla) ; the circles=whorls, and the dcts on circles= 
missing members ; crescentic marks=lodicules, the kidney-shaped=stamens ; the inner- 
most symbol with its half-circles represents stigmas, and its cavity the ovary. A Flower 
of Bambusa with outermost whorl missing, but full complement of members in the other 
whorls. 8 Common type of grass-flower with several members absent ; one stamen is 
anterior (next the flowering glume), the other two are posterior (against the palea). 
myurus.' The flowers of the genus Bamdbusa (bamboos), fig. 11 A, 
are perfectly regular, having three lodicules, six stamens, and three 
stigmas, the formula being Ko, C3, A3+3, G(3). If we regard the 
flower of the Lily family (K3, C3, A3+3, G3) as typical of Mono- 
cotyledons, and compare with it the flower of Bamdusa, we find 
that the latter only differs in having the outermost perianth whorl 
of three segments suppressed, and in the innermost (fifth) whorl 
being modified by the carpellary leaves uniting to form a unilocular 
instead of a three-celled ovary. 
As a rule the flowers of grasses are bisexual or perfect ; although 
there are many instances of one or more imperfect (usually male) 
flowers in the same spikelet with bisexual ones, e.g. Arrhenatherum 
and Panicum. In tropical and subtropical regions, we sometimes 
find a complete separation of the sexes, as in Zea mays whose 
spikelets are always unisexual, those in the upper part of the in- 
florescence containing stamens only, the lower spikelets female. 
In most grasses, the flowering glume diverges widely from the 
palea at the time of flowering, the anthers become pendulous, and 
the stigmas protrude one at each side of the flowering glume. In 
other cases the divergence or opening is just sufficient to let the 
anthers and stigmas emerge at the apex, either simultaneously or 
the stigmas first. The pollen cannot be scattered upon the stigmas 
of the same flower, when the anthers are pendulous, and its trans- 
ference from one flower to another (cross-fertilization) is effected 
by the wind. A little reflection will show that the peculiarities of 
the structure of: the grass-flower are all an extreme adaptation to 
