BLAKE: REVISION OF THE AVOCADOS II 



other forms occur in South America which, through lack of 

 sufficient material, cannot be definitely placed. One is the 

 plant described as P. gratissima var. melanocarpa by Philippi,^ 

 a single specimen of which is in the National Herbarium. It 

 is peculiar in its comparatively large bracts and subsimple pan- 

 icles shorter than the peduncles. The other, collected by Mr. 

 Pittier near Caracas (no. 5913), has a glabrous ovary, pubescent 

 style, and unusually long stipes to the glands of the third series 

 of stamens. Both these forms are best left in abeyance until 

 further material becomes available. 



The avocados-^ occurring in North America and the West 

 Indies may be distinguished by the following key : 



Perianth densely griseous-puberulous on both sides; staminodes pubes- 

 cent. 

 Ovary pubescent; staminal glands stipitate. 



Pedicels i to 6 mm. long; staminode with triangular head, much 

 broader than its stipe. 

 Branchlets glabrous to pilosulous, leaves glabrous to pilosulous 

 beneath; filaments 2 to 3 times as long as the anthers; head 

 of staminode much shorter than the stipe. 

 Leaves not anise-scented ; perianth deciduous. .1. P. americana. 

 Leaves anise- (or sassafras-) scented • perianth usually per- 

 sistent I a. P. americana drymifolia. 



Branchlets fulvous- villous ; leaves fioccose-tomentose beneath; 

 filaments only one-third longer than the anthers; head of 



staminode about equaling or exceeding the stipe 



2. P. Hoccosa. 



Pedicels 8 to 15 mm. long; stipe of staminode twice to thrice as 



long and essentially as broad as the elliptic head; branchlets 



densely ferruginous-tomentose 3. P. schiedeana. 



Ovary glabrous; staminal glands sessile 4. P. cinerascens. 



Perianth sparsely pilosulous outside, essentially glabrous within; 

 pistil and staminodes glabrous 5. P. leiogyna. 



* Anal. Univ. Chil. 91: 501. 1895. 



* The avocados form a small group of the subgenus Eupersea Mez, characterized 

 by their comparatively large flowers (usually 6 to 8 mm. long) with equal or only 

 slightly unequal perianth segments. Of the species here considered, the most im- 

 portant commercially are P. americana, P. americana drymifolia, and P. leiogyna. 

 P. schiedeana also has a large and well-flavored fruit, but is of little importance at 

 present outside of its native habitat. P. cinerascens, and presumably P. floccosa, 

 bear fruits too small to be of any value. 



