34 



ANGIOSPERMAE—DICOTYLEDONES 



1756. A. alpina Spreng. (= Arbutus alpina L.). (Warming, 'Arkt. Vaxt. Biol.,' 

 pp. 13-18.) — Tiiis species has so far been investigated in northern habitats, but not 

 in alpine ones. The pendulous ovoid flowers are 5-6 mm. long, and arranged in 

 short terminal racemes. Warming says that in Greenland they are either homogamous 

 or feebly protogynous. In that country the plant blossoms very early in the neigh- 

 bourhood of snow- and ice-fields, and sets fruit abundantly. There is a strong 



autogamous tendency, for 

 .^\3 the pollen falls very easily 



on the large sticky stigma 

 which lies below the anthers, 

 and this is found to be 

 dusted with it soon after 

 the flower opens. The fall 

 of pollen is checked, how- 

 ever, by the narrow opening 

 of the corolla and the hairs 

 which line it. The appen- 

 dages of the anthers are less 

 well developed than in A. 

 Uva-ursi, and in specimens 

 from Greenland may be en- 

 tirely absent. l^Cf. Fig. 220.) 



520. Arbutus L. 



1757. A. Unedo L. 



(Sprengel, 'Entd. Geh.,' pp. 

 240-1.) — 



Visitors. — Schletterer 

 observed at Pola — i. The 

 beautiful humble-bee Bombus 

 argillaceus Scop., on fine 

 days in November and 

 December; 2. Bombus ter- 



rester Z., freq., in September, October, and November. — 



' On sunny days when there was no wind it was also occasionally seen in 



January. I noticed it frequently during the Christmas season up to the end of 



January on the late blossoms of the strawberry-tree.' 



1758. A. Andrachne L. (Entleutner, Ost. bot. Zs., Wien, xxxix, 1889.) — 



Visitors. — In some of the flowers of this species at Meran, Entleutner noticed 

 small Muscids held fast by the tangled hairs, suffering the penalty of death for their 

 greediness. He also mentions that some insects had ' bitten through the flower-urn 

 close to the calyx.' 



Fig. 230. Arciosiaphylos alpifia, Sprettg. (after E. Warming). 

 A^ B. External view and longitudinal section of a flower; though 

 only just opened, the pollen has fallen from the anthers (X 4). C. An 

 anther from the same flower ; there are no appendages. D. Longi- 

 tudinal section through a flower with a tolerably short style { x 8). 

 £", Fy G. Anthers and filaments in various positions and of different 

 ages {X 20). H, I. Anthers from a bud (x 20). K. Longitudinal 

 section through a flower with a long style. L. Limb and opening 

 of a corolla, from below; the stigma can be seen within the latter 

 (limb about 2J mm. and aperture i mm. in diameter). M. Tetrad of 

 pollen-grains. 



