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, Eriocaulonese, &c. 

 Sometimes however the outer perianth-whorl is green and sepaloid, the inner whorl 

 larger, delicate, and petaloid {Canna, AUsma, 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 Cannaceae 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 GyncBceum 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, Iridese, Amaryllideae, Scitamineae, 

 Orchideae, &c.). The formation of three or more monocarpellary ovaries is limited 

 to the alliance of the Juncagineae and Alismaceae, 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 similar perianth-leaves into a tube in Hyacinthus, Con- 

 vallarta, Colchtcum, &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 orthotropous 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 ^/{o) + (o.i2.i) Q. 



S S 2 



