544 



PHANEROGAMS. 



another that the two lobes lie in one line above the apex of the filament, as in many 

 Labiataj. Not un frequently the filament also has appendages ; as, for example, the 

 membranous expansions or appendages right and left below in Allium which 

 resemble stipules, or a hood -shaped outgrowth behind as in Asclepiadeae, or ligular 

 structures in front as in Alysswfi t?ionlanum, or conical prolongations beneath on 

 one side as in Crambe, or on both as in Mahonia (Fig. 362, x). 



A phenomenon of great importance from a morphological point of view is the 

 branching of stamens which occurs in many Dicotyledons, a peculiarity of structure 

 which was erroneously confounded by the older botanists with their cohesion, 

 although the two are fundamentally distinct. Sometimes the branching of stamens 

 takes place, like that of foliage-leaves, bilaterally in one plane, right and left of the 

 median line, so that the branched stamen has a pinnate appearance, as in Calo- 

 thamnus (Fig. ^d^, si), where each division bears an anther. In other cases the 

 branching takes place in a kind of polytomy, as in Ricinus (Fig. 366), where the 



Fig. 365.— Long^itudinal section of the flower of Calo- 

 thamnus ;ythe ovary, j calyx,/ petals,^ style, j-/ branched 

 stamens. 



Fig. 366.— Part of a male flower of Ricinus communis 

 cut through lengthways ; yy the basal portions of the 

 compoundly-branched stamens ; a the anthers. 



separate stamens arise in the form of simple protuberances from the receptacle, each 

 one repeatedly producing new protuberances, which at length develope by inter- 

 calary growth into a corapoundly and repeatedly branched filament; the ends of 

 the branches all bearing anthers. In the Hypericinese \ three or five large broad 

 protuberances (Fig. 367, II-V, a) spring from the periphery of the floral axis after 

 the formation of the corolla, on each of which smaller roundish knobs are produced 

 in basipetal succession from its apex ; these latter become the filaments, each of 

 which eventually bears an anther, and are connected at their base with the primordial 

 protuberance of which they are branches. A horizontal section through the flower- 

 bud before the opening of the flower shows, especially in Hypericum calycinum, the 

 numerous filaments which spring from one original protuberance densely crowded 

 into one bundle. In this and many similar cases the common primordial basal 



^ [For further details see Molly, Unters. lib. die Bliithenentwickelung der Hypericineen und 

 Loasaceen, Diss, Inaug. Bonn, 1S75.] 



