530 WESTER: POLLINATION EXPERIMENTS WITH ANONAS 
study of the flowers and pollination of the sugar apple and the 
custard apple, the flowers of which superficially appeared to be 
identical with those of the cherimoya. It was then found that 
these two species were likewise proterogynous. In the course 
of this investigation it was noted that the flowers of the cherimoya 
and the custard apple shed their pollen in the afternoon from about 
3.30 to 6 P.M. In the sugar apple the pollen is discharged in 
the morning from the rising of the sun to about 9 A.M., when 
practically all the pollen is shed. After examinations of a large 
number of trees of this species three were found to shed their pollen 
in the afternoon and the interesting fact was noted that this 
phenomenon does not occur on the same trees in the morning. 
A more limited number of trees of the custard apple and the cheri- 
moya were available for observation; were it extended to a large 
number it is quite probable that individual trees may be found 
that shed their pollen at other times of the day than has been 
noted in the course of these observations. 
The flowers of the three species enumerated, belonging to 
the section Aftae Martius, are nodding; the calyx is tripartite, 
the sepals small and triangular; the six petals are arranged in 
two rows, the three exterior ones being linear-oblong with an 
obtuse sometimes acute apex; outside, these petals are ferru- 
ginous-tomentose and velvety in the cherimoya, while in the 
custard apple and the sugar apple they are greenish and sparsely 
hairy. The petals are shortest in the custard apple, being some- 
times only 16 mm. long; in the cherimoya they frequently exceed 
30 mm. in length. In all species they are keeled inside, whitish, 
concave, with a maroon blotch in the cavity, at the base; the 
interior petals are rudimentary; the number of stamens, which are 
attached to the torus, is indefinite and they cohere by a connective 
gland beyond the anthers, surrounding the syncarpium in which 
an indefinite number of carpids are united. As the flowers be- 
come full grown a viscid fluid is secreted that covers the syncar- 
pium and which appears to be most abundant about twenty-four 
hours before the pollen is shed. 
Until the shedding of the pollen the petals assume an almost 
perpendicular position (see FIGURES I and 3a) and leave a small 
opening, facing downward, for the entrance of pollen-bearing 
