440 FOURTH GROUP. SEED-PLANTS. 



Scitamineae. Considering the extensive abortion in small flowers it may sometimes 

 be a question whether in a group of stamens and carpels we have a single flower 

 before us, or an inflorescence of several flowers reduced by abortion, as for instance 

 in Lemna. 



When both the perianth-whorls are developed, they are generally of the same 

 structure ; and in large flowers they are usually delicate and petaloid and either 

 coloured or not, as in the Liliaceae and Orchideae ; in small flowers on the contrary 

 they are firm, dry and membranous (glumaceons], as in the Juncaceae and Eriocau- 

 loneae. But sometimes the outer whorl is green and sepaloid, as in Canna, Ali'sma, 

 Tradescantia. 



The stamens are generally composed of a filiform filament and a quadrilocular 

 anther ; but variations are not infrequent, especially in the form of the filament and of 

 the connective. Among the most remarkable are the petaloid staminodes of the 

 Canneae and Zingiberaceae. Naias and Typha^ appear to supply exceptions to the 

 rule that the stamens are of foliar origin, as has been already pointed out (p. 353). The 

 branching of stamens, which is of so frequent occurrence in the Dicotyledons, scarcely 

 ever occurs in the Monocotyledons, and this corresponds to the usual absence of 

 branching in the other foliar formations; if the diagram of the flower of Canna 

 (Fig. 369) founded on Payer's statements is correct 2 , the petaloid staminodes are 

 branched. 



The gynaeceum usually consists of a trilocular ovary ; it is less often unilocular 

 and trimerous ; in both cases it may be superior or inferior, the latter only in plants 

 with large flowers, as Hydrockaris, the Irideae, Amaryllideae, Scitamineae, and series 

 of the Gynandrae. Three or more monomerous ovaries, polycarpous flowers 

 therefore, are found only in the Juncagineae and Alismaceae, in which also the usual 

 number of the members and whorls of the gynaeceum is exceeded, reminding us of 

 the Polycarpicae among the Dicotyledons. 



Cohesions and displacements are usually neither so frequent nor so complicated 

 in the flower of Monocotyledons as in Dicotyledons. Among the most remarkable 

 cases of the kind are the formation of the gynostemium in the Orchideae, the cohesion 

 of six similar perianth-leaves into a tube in Hyacinthus, Convallaria, Colchicum, etc., 

 the epipetalous and episepalous position of the stamens in some plants ; this last 

 peculiarity is much less constant within fixed limits in Monocotyledons than in 

 Dicotyledons. 



Terminal flowers on a leafy primary shoot are very rare in Monocotyledons 

 (T.ulipd), terminal inflorescences are more common. 



As the flower increases in size it exhibits a tendency on the whole to the zygo- 

 morphism which is in many cases only feebly indicated, but appears most fully 

 developed in the Scitamineae and Orchideae. 



The ovules usually spring from the margins of the carpels, rarely from their 

 inner surface, as in Bulomus ; the single orthotropous ovule of Naias is formed, 

 according to Magnus, by the transformation of the extremity of the floral axis ; one 



1 Bot. Ztg. 1882, p. 405. 



2 This is not quite the case according to Eichler's careful researches. But the construction of 

 the flower in this genus is so difficult, that we must not attempt to describe it here. See Eichler, 

 BKithendiagramme, I. 



