9 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
stamens, as in A. syuamosa (fig. 1), or they may be entirely wanting, as 
in A. acuminata (fig. 2). In species where they are normally absent 
inner petals sometimes occur, either 
in the form of small stamen-like 
bodies with a pair of sterile pollen 
sacs on their back, or as miniature 
petals clothed with an indument 
more or less like that of the outer 
petals. Sometimes one or more 
inner petals are abnormally de- 
veloped and thrust themselves be- 
tween two of the outer petals, as 
in the Annonella of Santo Do- 
mingo (Annona roset); while in 
A. cornifolia and the closely allied 
A. nutans, to be described here- 
after, the flower has a 6-lobed 
gamopetalous corolla composed of 
3 narrow lobes alternating with 3 
broad ones, approaching somewhat 
the structure of a Rollinia flower ; 
and in several species abnormal 
flowers occur which have a 4- 
parted calyx and 8 petals or a 
2-parted calyx with 4 petals, in 
each case in 2 series. 
Fia, 1.—Flower of Annona squamosa. a, Fig, 2.—Flower of Annona acumt- 
Stamens; d, carpel;c,inner petal. Flower nata. Natural size, 
scale 4; a,b,c, scale 6. 
The essential parts (pl. 2) consist of an andreecium, composed of 
numerous stamens closely crowded on a convex or conoid receptacle 
EXPLANATION OF PLATE 2.—Gyneecium surrounded by andrecium, A, seen from above; 
B, from the side, with part removed. Photographed from material in the U. S. National 
Herbarium by Albert Mann, Scale 6, 
