49 ANGIOSPERMAEMONOCOTYLEDONES 



Visitors. Herm. Miiller often observed hundreds of individuals of Psychoda 

 phalaenoides L. (identified by Winnertz, and = P. nervosa Mg., perhaps also 

 Tipula nervosa Schr.). I have also noticed similar numbers of the same species in 

 woods near Eutin. 



2909. A. italicum Mill. (Delpino, op. cit.; Knuth, ' Blutenbiol. Beob. a. d. 

 Ins. Capri/ pp. 16-21.) The flower mechanism in this species corresponds exactly 

 to that of A. maculatum. While in the bud stage the inflorescence is firmly sur- 

 rounded by the large spathe, which is still green in colour, this gradually becomes 

 lighter and its upper part unfolds so that the yellow tip of the spadix becomes visible. 

 In the mature stage the spadix of plants in Capri reach a length of 8 or even 10 cm., 

 and two-thirds or three-quarters of it are yellow in colour and up to 1*5 cm. in 

 diameter, while the lowest third or quarter is contracted into a sort of stalk 6 mm. 

 long and concealed in the narrow part of the spathe. 



Below the narrowest part of the spadix there are several whorls of vestigial 

 flowers, attached to a thickened region, and produced into stiff bristles 5 mm. long 

 and directed obliquely downwards. They touch the wall of the trap. A piece of the 

 spadix only a few millimetres long divides them from the numerous male flowers, 

 arranged in 5-7 whorls, and each consisting of but a single stamen. Immediately 

 below these are situated several whorls of vestigial female flowers with almost vertical 

 style-like processes about 5 mm. long, and finally, below these, the female flowers, 

 also arranged in 5-7 whorls. Each of the latter consists only of an ovary directed 

 obliquely upwards, with a stigma on the outer side, which has the appearance of 

 a roundish spot not quite one mm. in diameter. 



The female flowers mature before the spathe opens, while the male ones do nol 

 shed their pollen until after the ovary has shrivelled. The stigma, hitherto of 

 whitish-yellow colour, scarcely distinguishable from the ovary in colour, is then ol 

 a brownish tinge, while a large mass of pollen fills the base of the trap. After th 

 anthers have scattered the pollen, the spathe fades, and the upper, yellow part ol 

 the spadix then usually falls off". When the trap-hairs shrivel, the lower narrow( 

 part of the spadix with the female flowers falls off" also, the spathe withers entirely] 

 and the fruits ripen. 



Arcangeli (Nuovo Giorn. bot. ital., Firenze, xv, 1883) states that the infloi 

 escences open towards i p.m. and reach full maturity between 3-5 p.m. The stag< 

 of maturation are the same as those of Dracunculus vulgaris Schott. The odour 

 not perceptible. Arcangeli describes it as a mixed smell of mice, lemon, and decayei 

 vegetable matter. The spathe also possesses an odour of magnolia or fruit a1 

 its base. 



The pollinators are small flies which feed on decayed vegetable matter, 

 Arcangeli counted 239 small Diptera in 56 inflorescences, 159 of them belongin] 

 to the genus Psychoda. Only 1 7 were dusted with pollen, the others having alread] 

 deposited theirs on the stigma. 



With regard to the flowers of A. italicum, Arcangeli states that the increase 



the fact that, when a trap was cut open, all the contained insects flew out and made their way int 

 the trap of a second specimen held in readiness. It must be added that all the Arums so filled witl 

 Psychoda were in the second (male) stage of anthesis, with shrivelled stigmas and dehiscing anther 



