FERTILIZATION OF PHACELIA. 55 
it (fig. 3). The anthers now debisce, turning completely inside 
out in a manner to be described below, and present the whole of 
the pollen at once to visiting insects. The styles now bend 
slowly upwards, till at length they stand vertically and overtop 
the stamens (fig. 8, dotted lines); the second stage in the 
flower’s history now begins. Finally the corolla withers, but does 
not usually drop off, remaining adherent to the ripening fruit 
for some time. The stigmas, so far as a microscopic examination 
shows, seem to be receptive all through the period of flowering, 
but are certainly somewhat better developed in the later stage. 
The dichogamy of the flower gives it some chance of cross- 
fertilization, especially as it is largely visited (in Cambridge) for 
honey and pollen’; but it seems probable that self-fertilization is 
more common, even when it is visited by insects. The flowers are 
closely packed together, and hence in the early stage the style of 
one flower overlaps into the next, and during the upward move- 
ment comes amongst the anthers of the other flower. Insects 
crawl over the whole mass of flowers, touching stamens and styles 
indiscriminately, and probably often knock pollen on to the 
stigmas from the surrounding anthers. The commonest visitors 
in Cambridge are honey-bees, various species of Bombus, and 
many Syrphide. The last-named seem usually only to collect 
pollen, the bees both pollen and honey. Every flower on the 
plants examined set a full complement of seed. An attempt 
was made to determine if seed were set when insects were ex- 
cluded, but the plant became very unhealthy under the muslin 
net and its flowers did not open properly. 
P. Campanularia.—The inflorescence is of the usual cymose 
type, but single instead of fascicled. The flowers also are 
widely separated, so that insects must fly from one to another, 
and are much larger that in the preceding species. The calyx 
and peduncle are hispid and glandular as in P. tanacetifolia. 
The corolla is campanulate and of a deep azure-blue colour. It 
increases considerably in size whilst open, as may be seen from 
the figures (figs. 7 and 8), which are drawn from photographs. 
In the earliest stage the total depth is about 15 mm., the 
total width about 18 mm, while the depth and width of the 
actual tube are each about 10 mm. In the latest stage these 
dimensions become about 20, 21, 15, 11 mm. respectively. There 
is no scent, and the attractiveness of the flower, asin all the 
species examined, rests upon its conspicuousness. 
