MONOCOTYLEDONS . 
62J 
When both the perianth-whorls are well developed, they are usually similar in 
structure; in large flowers they are generally delicate and petaloid and either 
brightly coloured or not (Liliaceae, Orchidese, &c.) ; in small flowers on the con- 
trary they are firm, dry, and membranous, as in Juncaceae, Eriocauloneae, &Co 
Sometimes however the outer perianth-whorl is green and sepaloid, the inner whorl 
larger, delicate, and petaloid {Canna, Alisma, Tradescantid) ; in the very small and 
closely crowded flowers of the Glumiflorae, the perianth-leaves, when present, take 
the form of hairs (the setae of Cyperaceae) (Fig. 426), or of small membranous scales 
(the lodicules of Grasses). 
The Stamens generally consist of a filiform filament and a quadrilocular anther ; 
though variations frequently occur, especially in the form of the filament and 
connective. Among the most striking deviations from the ordinary type are the 
petaloid staminodes of Cannacese and Zingiberaceae. It has already been pointed 
out (pp. 491, 541), that the foliar nature of the stamens is subject to an exception 
in the Naiadeae (at least in Naias) according to the researches of Magnus. The 
stamens of Monocotyledons scarcely ever branch, as is often the case in Dicoty- 
ledons ; and this corresponds to the customary absence of branching in the other 
foliar structures also. If the diagram of the flower of Canna (Fig. 430), drawn 
according to Payer's description, is correct \ the petaloid staminodes are branched. 
The GyncEceum has usually a trilocular ovary ; less often it is tricarpellary but 
unilocular ; in both cases it may be either superior or inferior, but the latter occurs 
only in plants with large flowers {Hydrocharis, Irideae, Amaryllideae, Scitamineae, 
Orchideae, &c.). The formation of three or more monocarpellary ovaries is limited 
to the alliance of the Juncagineae and AHsmaceae, in which the ordinary number 
of members and of whorls of the gynaeceum is also exceeded, reminding one of 
the Polycarpae among Dicotyledons. 
Adhesion and displacement are not so common in the flower of Monocoty- 
ledons, and usually not so complicated as among Dicotyledons ; among the most 
striking phenomena of this nature are the formation of the gynostemium of Orchids ; 
the cohesion of the six simOar perianth-leaves into a tube in Hyacinthiis^ Con- 
vallaria, Colchicum, &c. ; and the epipetalous and episepalous position of the 
stamens in the same plants and in some others. Adhesion of the stamens to the 
calyx or corolla occurs much less constantly in particular families among Mono- 
cotyledons than among Dicotyledons. 
Terminal flowers to a leafy primary shoot occur very rarely among Mono- 
cotyledons {e.g. in Tulipa)', terminal inflorescences are more common. The flower 
acquires a tendency to zygomorphism, especially as it increases in size ; but this is 
often only feebly indicated, and attains its highest development in Scitamineae and 
Orchideae. 
The Ovules of Monocotyledons usually spring from the margins of the carpels, 
rarely from their inner surface (as in Butomus) ; the single ortholropous ovules of 
Naias (according to Magnus) and Typha (Rohrbach) arise by the transformation of 
^ According to Eichler's masterly description of the flower of Canna (Bot. Zeitg. 1873) the 
relations of the androecium are not quite those expressed in the diagram Fig, 430. Eichler gives the 
formula as being ^3 P3 6'/ (0) + (0.12.1) Q. 
S S 2 
