KiiKK — Disehidia rafflesiana and Dischidia nummularia. 297 



several batclies from different plants that I discovered two species were 

 involved. 



In D. rafflesiana tlie ants make their nests within the pitchers, and also 

 plaster clay about the bases of the pitchers, and over tlie attaching roots. I 

 was not able to examine such a large series of this species, as it was not quite 

 so abundant as D. mimm%ilaria, and is usually more inaccessible, growing 

 near the tops of large trees. I followed the same procedure as for 

 D. nummularia, only counting one plant on each tree, and omitting any 

 plant growing on the same tree as D. nninniularia. 



In all, forty-five plants were examined, and in forty-four of these the 

 nests of the same two species of Iridomyrmex were found in one or more of 

 the pitchers of eaoli plant. The single exception was a young plant with only 

 one small pitcher. No runs were seen near it or on the same tree. These 

 facts warrant us in drawing the same conclusion with regard to D. rafflesiana, 

 i.e. that in Northern Siam it is usually associated with a species of 

 Iridomyrmex. 



Structure of Flowers and Pollination. 



In both D. rafflesiana and D. nuDtinularia the flowers are borne in sliortly 

 stalked umbels in the axils of the leaves, of either the foliage or pitcher 

 leaves in the case of D. rafflesiana. In both species only one or two flowers 

 in each umbel open at a time. 



The flowers of D. rafflesiana are about 07 cm. long ; tliey are of a greenisii 

 colour, with brown longitudinal lines fi'om about one-third of the way up the 

 corolla to its tip. These lines mark tlie adjoining edges of the petals ; the 

 petals are free for somewhat less than one-third the length of the corolla, but 

 remain in close apposition. When the flower opens, the tips of the petals 

 separate slightly, not sufficiently to admit the passage of an ordinary pin ; 

 this entrance is protected within by a circle of stiff, inwardly pointing hairs. 

 From the base of the staminal column spring five bicoruuate appendages, the 

 adjacent horns of which meet and form a circle round, but at some distance 

 from the column at the level of the clips. The edges of the anthers are 

 produced into wings narrow above but broadening out below ; the edges of the 

 wings of adjoining anthers meeting for the greater part of their length form 

 a long, narrow chamber ; in the lower part of this chamber, however, the 

 boundary is formed by the thickened median portions of the wings, the edges 

 of the wings being here turned outwards to form a short furrow. The ovary 

 and the greater part of the style are surrounded by the staminal column. 

 The style is expanded in the middle and again, to a lesser extent, at its free 



