150 Transactions of the Society. 



showy central spadix, the peculiar smell, the prospect of honey, and 

 perhaps of shelter, enter the tube while the stigmas are mature, 

 and find themselves imprisoned by the fringe of hairs, which, while 

 permitting their entrance, prevent them from returning. After a 

 while, however, the period of maturity of the stigma is over, and 

 each secretes a drop of honey, thus repaying the insects for their 

 captivity. The anthers then ripen and shed their pollen, which 

 falls on and adheres to the insects. Then the hairs gradually 

 shrivel up and set the insects free, which carry the pollen with 

 them — so that those which then visit another plant can hardly fail 

 to deposit some of it on the stigmas. Often mure than a hundred 

 small flies will be found, and in one case Knuth counted no less 

 than 4000 in a single Arum. 



Another explanation of the floral mechanism in A. maculatum 

 has recently been suggested by Father Gerard. He considers that 

 the honey secreted by the stigmas has a stupefying effect on the 

 insects, which are killed and ultimately digested in the interior 

 of the spathe. The insectivorous habit is deduced from the 

 presence of dried remains of flies on the walls of the cavity. 

 Schnetzler had previously claimed a similar insectivorous habit 

 for A.crinitum. Self-pollination is not, he thinks, precluded in 

 A. maculatum, some of the stigmas being still functional when the 

 anthers dehisce. 



The mature fruit is sometimes 12-14 mm. in diameter, this 

 being made up of the fleshy ovary, which becomes pulpy, or baccate, 

 and bright scarlet at maturity. The base of the spathe is per- 

 sistent for a time, but the cluster of swelling fruits bursts it, 

 leaving the fruits exposed in a very prominent manner, especially 

 when the scarlet fruit colours up. By this time the leaves have 

 also died away, leaving the stout scape with its scarlet fruits ex- 

 posed as an attraction to the agents that disseminate the seeds, 

 presumably birds. 



The other vegetation in copses and under hedges dies away at 

 the same time as the result of the intensified shade of the leafage 

 of the trees and bushes above them. All the plants thus asso- 

 ciated have completed their natural growth, and the principal 

 event in the case of the Arum is the dissemination of the seeds. 



One of the largest fruits examined contained only two perfect 

 seeds, and two unchanged infertile ovules. Occasionally these 

 seeds are matured. The fruit is 1-celled, and the seeds are basal, 

 or nearly so, erect, and orthotropous. The seeds are globose or 

 obovoid, 4-5 mm. in diameter, and pale yellow. The testa is greatly 

 thickened, and leathery or crustaceous, deeply pitted, with the pits 

 arranged in longitudinal lines. The micrdpyle is prolonged, form- 

 ing a mucro, while the base is also prolonged into a short, thick 

 funicle or stalk. In its early stages a thickened arilloid surrounds 

 this short stalk. 



