286 MR. J. C. WILLIS’S CONTRIBUTIONS TO 
taste, and is attractive to insects. The flowers swarm with 
Meligethes and Thrips, licking the stamens. Many Diptera also 
visit them for the same purpose. The ridge which continues the 
stamen inside the perianth-tube is also covered with cells like 
those described above. If astamen be scratched all over with a 
needle, so much fluid exudes that it trickles down into the base 
of the flower, and may accumulate there to some depth. These 
peculiar cells develop early, and are found in quite small buds. 
Shortly after the flower opens, the three short stamens dehisce 
and cover the stigma with pollen (fig. 1). Its papilla, however, 
are at this period very short, and apparently not receptive. Of 
flowers left to themselves, a large number do not set seed. After- 
wards the flower increases in size (cf. Pl. X VIII. figs. 1 and 4), 
but the ovary grows most rapidly till the stigma is level with the 
long stamens ; its papille are now very long and fully developed. 
The mouth of the flower is narrow, and insects probing the tube 
for honey must touch both anthers and stigma. Self-fertilization 
does not regularly occur; but may happen, especially when the 
flower finally shrivels up. The only insect visitors observed were 
those mentioned above, which did not usually effect fertilization ; 
and it is not altogether evident how the flower is regularly fer- 
tilized, as it is much easier for insects to get honey by biting 
the stamens than by probing the flower in the proper way. 
The above-described fertilization method does not agree very 
closely with that of any of the hitherto described Liliacew. 
Allium resembles it in the protandry, and Zloydia and Liliwm 
also approach it in some measure, especially the latter, whose 
nectary, inserted on the perianth, gives a possible clue to the 
peculiar mode of nectar-secretion, if such it can be called, in 
Brodiea. 
Stanhopea tigrina, Bateman.—The mode of pollination of 
8. oculata was studied by Darwin*; but he failed to fertilize 
the flowers on account of the narrowness of the stigmatic 
chamber, which prevented the entrance of the pollinia. 8. tigrina 
flowered profusely in the Cambridge Botanic Garden during 1893, 
and Mr. Francis Darwin suggested to the author that it should be 
carefully studied. This has been done, and the insertion of the 
pollinia has been easily managed; but it was found impossible 
to completely understand the flower on account of the want of 
the insects that in its native place (Mexico) probably pollinate it. 
The hypothesis as to the mechanism of the flower advanced below 
* ‘Fertilization of Orchids,’ p. 171. 
