CONCRESCENCE 



55 



which have been examined up to the present, that both these views of 

 the ovary are in a certain sense right, although they must be combined 

 together. Upon this subject more will be said in the special part of this 

 book. 



I may here by means of Figures 23 and 24 shortly explain another 

 example. The spadix of the Aroideae is invested by a bract, commonly 

 designated a spathe, which arises below it. Spathiphyllum platyspatha 

 is peculiar in having the spadix concrescent throughout its length with 

 the spathe, and the flowers arise only upon the free slightly-projecting 

 side of the spadix opposite to that which is concrescent with the spathe. 

 A transverse section through the spadix (Fig. 24, ///) awakens the 

 suspicion that the flowers spring out of the upper side of the spathe which 

 by its inturned edges surrounds in a protecting manner the inflorescence. 

 The history of development shows however that the spathe is laid down 



z. 



FlG. 24. Spathiphyllum platyspatha. Development of the inflorescence. / and // young- inflorescences upon 

 which is seen the primordium of the spathe sprouting laterally beneath the vegetative point of the inflorescence. 

 The leaf opposite the inflorescence will become a scale-leaf in the axil of which a continuation-shoot will arise, 

 ///transverse section through a young inflorescence, /^diagrammatic figure to illustrate the ' concrescence.' 



quite normally below the apex of the spadix (Fig. 24, / and 77), but, 

 instead of the portion of the spadix above the point of origin of the spathe 

 growing, as is usual, and becoming covered with flowers, the zone of 

 it which is united to the spathe develops greatly (this zone is shaded in 

 the diagram, Fig. 24, IV] and attains maturity, consisting outwards of the 

 inflorescence axis (in Fig. 24, IV, the portion to the right), and inwards 

 of the base of the spathe ; and thus by the united growth of the shoot- 

 axis and the leaf-insertion the wonderful structure from which we 

 started is produced. Other species of Spathiphyllum show this con- 

 crescence in much less degree and only at the base of the spadix. We 

 do not know the biological relationships with which the peculiar change 

 in the course of development in Spathiphyllum platyspatha has been 

 connected. 



