1 
264 THE FERTILISATION OF FLOWERS. [PART II. 
numerous as those of Z. angustifolium. For while in the latter d 
species distinct proterandrous dichogamy and the change in posi-— 
tion of the reproductive organs have quite excluded self-fertilisation, 
it remains possible in £, hirsutum. The stigmas here od dal 
simultaneously with the anthers: cross-fertilisation is insured in 
case of insect-visits by the more prominent position of the stigmas 
but in absence of insects the stigmas curl backwards, and come ind 
contact with the pollen of the eee stamens. 
Epilobiuin alpinum, L., produces seed by self-fertilisation im 
the absence of insects (Axel, No, 17). 
A review of the foregoing species of Hpilobium brings us to thell . 
same result that a comparison of the Geraniums, Polygonums, — 
Alsinew, etc., leads us to, and confirms the view that no general — 
deduction for a whole genus can be drawn from the floral mechanism , 
of a single species, but that each new species must be investigated _ 
afresh. When Delpino (175A) characterised the genus Hpilobiwm 
as dichogamic and fertilised exclusively by bees, this description - 
may perhaps have been true of some particular species that I am 
unacquainted with; but it certainly cannot be sustained for the 
whole genus, 
— 
ae Se Sites 
169. GENOTHERA BIENNIS, L.—The structure of this flower was 
minutely explained by Sprengel. The flower opens and is most 
strongly odorous in the evening, and seems to have adapted itself in 
this way to crepuscular and nocturnal Lepidoptera. But not only 
is the pollen exposed to bees and flies, as in the nocturnal flowers 
hitherto described, but the honey also is accessible to long-tongued 
bees. The colour of the flower is not white, as most nocturnal 
flowers are, but bright yellow, and the flower remains open or 
partially open dicing the day ; so that it is probably more correct 
to look upon the flower as adapted simultaneously for bees and — 
nocturnal Lepidoptera. 
Visitors: A. Lepidoptera—Sphinges: (1) Macroglossa stellatarum, L., 
towards evening, sucking without settling on the flower. This species was_ 
probably observed by Sprengel also (No. 702, p. 221). B, Hymenoptera—A pide : 
(2) Bombus lapidarius, L. 9; (3) B. silvarum, L. 2; (4) B. agrorum, F. 9, | 
all three sucking ; (5) Apis mellifica, L. $, s.ande.p. ; (6) Colletes Davieseana, 
K. 2, ¢p.; (7) Panurgus calcaratus, Scop. ? é dusting itself with the pollen. 
C, Diptera®-Syrphide ; (8) Eristalis tenax, L. ; (9) E. arbustorum, L. ; (10) 
E. nemorum, L,; all three feeding on pollen, very abundant. 
Gnothera sinuata, Mx.—Trelease saw this flower visited by 
Ruby-throated Humming-birds (731). 
