550 THE FERTILISATION OF FLOWERS. [PART ILI. 
with pollen. In absence of insects, self-fertilisation takes place 
regularly, as Hildebrand has shown (351); for the anthers stand 
close round the style and apply their pollen to the marginal 
papille of the trilobed stigma. 
390. CONVALLARIA MULTIFLORA, L.—The honey lies at the 
base of the flower between: the perianth and the ovary. The 
length of the perianth tube, which is 11 to 15 mm. long (or even 
18 mm. in cultivated plants) protects the honey from short-lipped 
insects, and the pendulous position of the flower protects it from 
rain. Humble-bees visit the flowers; they thrust their heads into 
the wide part of the tube, and touch the stigma which stands 
in the mouth of the flower, and the anthers which ripen simul- 
taneously with it, with opposite sides of their heads or tongues. 
They thus effect cross-fertilisation regularly. In each flower the 
bee in touching one side of the stigma thrusts the opposite 
side against the anthers. In absence of insects, spontaneous 
self-fertilisation occurs. 
Visitors: A. Hymenoptera—A pide : (1) Bombusagrorum, F. 9 (12—15) ; 
(2) B. hortorum, L. 2 (19—21), s., hanging, back downwards, on the flowers. 
B. Diptera—Syrphide : (3) Rhingia rostrata, L. (11—12), very ab., often two 
at the mouth of the same flower,—sucking in vain for honey, which its tongue 
is too short to reach, then collecting pollen and occasionally effecting fertilisa- 
tion by stroking the stigmas. 
Convallaria verticillata, L., is adapted for fertilisation by bees ; 
C.. polygonatum, L., for fertilisation by humble-bees. The anthers 
and stigma are matured simultaneously, and, in C. verticillata at 
least, some pollen as it emerges from the anthers always reaches 
the stigma. It is probable that it is outstripped in its action by 
pollen brought from other flowers (609). 
| Asprdistra elatior, Blume.——Buchenau described the structure 
of the flower thoroughly, but was unable to elucidate its 
mechanism fully. Delpino, however, has endeavoured, with 
apparent success, to explain the mechanism of the flower, though 
he failed to find it visited by insects (118, 178, 360). 
The capitate stigma closes the flower, leaving only four small 
openings through which Delpino supposes small flies to enter; 
the pollen falls out of the anthers and lies in the cavity of the 
flower. The flies emerge all dusted with pollen, and alighting on 
the stigma of another flower place some pollen there before they 
find the small entrance. 
en ee aes 
