ONAGRARIEAE 441 



XLII. ORDER ONAGRARIEAE JUSS. 



300. Epilobium L. 



Flowers red, more rarely white, frequently arranged in large conspicuous 

 racemose inflorescences ; protandrous, homogamous, or protogynous ; with con- 

 cealed nectar secreted by the upper surface of the ovary. The pollen-grains are 

 usually bound together by threads of viscin. 



1040. E. angustifolium L. (=E. spicatum Lam., and Chamaenerion angusti- 

 folium Scop.). (Sprengel, 'Entd. Geh.'; Herm. Muller, 'Fertilisation,' pp. 261-2, 

 'Weit. Beob.,' II, p. 237 ; Lindman, 'Bidrag till Kanned. om Skandin. Fjellvaxt. 

 Blomn. o. Befrukt.' ; Warming, ' Bestovningsmaade af nogle gronlandsk. Blomster,' 

 pp. 32-3; MacLeod, Bot. Jaarb. Dodonaea, Ghent, vi, 1894, pp. 291-2; Kerner, 

 Nat. Hist. PI.,' Eng. Ed. 1, II; Schulz, 'Beitrage,' II, p. 73; Knuth, ' Bloemenbiol. 

 Bijdragen ' ; Loew, ' Blutenbiol. Floristik,' p. 394.) Kerner says that the purple-red, 

 rarely white flowers of this species, open between 6 and 7 a.m., and are protandrous 

 to an extent that precludes self-pollination, as Sprengel long ago observed. The nectar 

 secreted by the fleshy green top of the ovary is protected from rain, for the expanded 

 bases of the filaments converge to form a hollow cone, which grasps the base 

 of the style. Where the style leaves the cone it is covered with hairs which prevent 

 rain-drops from entering, while the proboscis of an insect can easily be pushed 

 through to the nectar. 



In younger flowers, the stamens (which are covered with pollen-grains bound 

 together by threads of viscin) serve as the only possible alighting-place for insects, 

 for the style is still short, and the stigmas apposed. In older flowers the dehisced 

 stamens curve downwards, while the now elongated style with its four diverging 

 recurved stigmas forms the only alighting-place, so that insects coming from younger 

 flowers must pollinate older ones. 



The flower mechanism does not always conform to the above description. 

 Warming states that the var. leiostyla is slightly protogynous along the Isortokfjord, 

 and therefore capable of self-pollination. According to Schulz, the flowers in the 

 lowlands are more distinctly protandrous than in the mountains (Tyrol), where 

 the stigmas are mature in some cases before the pollen is entirely shed. Kerner 

 says that the style, short at first, elongates after twenty-four hours, and the widely 

 diverging stigmas finally recurve so as to touch the pollen-covered anthers : hence 

 automatic self-pollination can be effected. Kerner found plants with normal flowers 

 in only a few places. In shady localities the flowers dry up and fall off; an attempt 

 is also made to overcome the disadvantages of unfavourable habitats of this kind 

 by the development of long runners. 



Visitors. Sprengel observed various humble-bees. I myself noticed 5 nect- 

 skg. bees. 



I. Apis mellifica L. ; 2. Bombus agrorum F. $ ; 3. B. hortorum Z. $ and $ ; 

 4. B. lapidarius Z. j, 5 and $ ; 5. B. terrester Z. 5 and $. 



Herm. Muller (H.M.) and Buddeberg (Budd.) give the following list. 

 A. Coleoptera. Cerambycidae : 1 . Strangalia melanura Z., nect-lkg. (H. M.). 

 B. Diptera. (a) Empidae : 2. Empis livida Z., freq., skg. (H. M.) ; 3. E. rustica 

 Fall., do. (H. M.). (b) Stratiomyidae: 4. Chrysomyia polita Z., skg. (Budd.). 



