ROSACE A E 343 



surface of the lower part of the cup-shaped receptacle. It is protected from rain and 

 unbidden guests by woolly hairs which cover the ovary and the lower part of the 

 style. The numerous stamens are inserted into the receptacle at very different heights, 

 so that some of the anthers are on a level with the stigma, while others project 

 beyond it. When the flower opens, the stigma is already mature ; the anthers 

 then gradually dehisce and get covered with pollen on all sides, so that in the 

 event of an insect-visit either cross- or self-pollination may take place. The latter 

 may also be effected automatical!)-. 



Visitors. — I have observed the following on cultivated plants {' Bloemenbiol. 

 Bijdragen '). — 



A. Diptera. Syrphidae: i. Eristalis tenaxZ., skg. and po-dvg. B. Hymeno- 

 ptera. {a) Apidae : 2. Bombus terrester L. 5, skg. ; 3. Halictus cylindricus F. 5, 

 do. The humble-bee usually alighted on the petals, and then crept under the 

 stamens to get at the nectar. In doing so it brushed the anthers with its back, 

 but did not touch the stigma. More rarely, it settled on the middle of the flower, 

 i. e. on the stigma, and then crept to the stamens, so that its under-surface was 

 covered with pollen: in this case cross-pollination was effected. (1^) Vespidae: 

 4. Vespa sp., skg. 



Ducke saw the rufous bee Osmia cornuta Ltr. 5 and J, freq., at Trieste. 

 Schletterer noticed 2 bees at Pola : — i. Bombus terrester Z.; 2. Xylocopa violaceaZ. 



On the foliage-leaves of this species there are extrafloral nectaries (Kirchner, 

 'Flora V. Stuttgart,' p. 461), which are visited by ants and wasps, that afford 

 protection against caterpillars and other harmful animals. 



818. A. nana L. ( = Prunus nana Stokes). — Kirchner has also described the 

 pollination of cultivated plants of this species (' Neue Beob. ii. d. Bestaubungseinricht. 

 einheimisch. Pfl.,' Stuttgart, 1886, p. 36). The length of the receptacle is 10 mm. 

 and the diameter of its throat is 4 mm. ; it narrows somewhat below. The 

 lower part of its inner surface is yellow in colour, and secretes nectar, which is 

 protected from rain and unbidden guests as in the last species, the ovary and 

 that part of the style included in the receptacle being beset with many woolly 

 hairs. The upper glabrous region of the style projects 2-3 mm. from the 

 receptacle. Here also the stamens are inserted at very different heights on 

 the cup-shaped floral receptacle, and the filaments are of various lengths, 

 so that the anthers of the shortest stamens are on a level with the stigma 

 or even lower, while those of the longer stamens project beyond it. When the 

 flower opens the anthers are still closed ; the already mature stigma is at first 

 covered by the stamens, which project vertically upwards. Subsequently the anthers 

 successively dehisce in no particular order, and get dusted with pollen all round, 

 so that automatic self-pollination can now readily take place. Whether this is 

 effective or not seems doubtful, as the numerous bushes observed by Kirchner but 

 rarely set fruits. 



242. Persica Tourn. 



Homogamous, bright rose-red flowers with concealed nectar, secreted in the 

 base of the receptacle. 



8ig. P. vulgaris Mill. ( = Prunus Persica Slokes and Amygdalus Persica Z.). 

 (Herm. Miiller, ' Weit. Beob.,' II, p. 244 ; Kirchner, ' Neue Beob. U. d. Bestaubungs- 



