ferences in such critical characters as the number of sta- 
mens, the size of the anthers, the length of the supra- 
staminal column, the size and form of the glandular lobes 
in the staminate flower, and the condition of the annular 
disk in the pistillate flower are taken into consideration. 
The very different form of the masculine buds—short, 
obtuse, even somewhat truncate in Hevea pauciflora var. 
coriacea, but extremely long and acuminate with the tips 
of the segments peculiarly spiral-imbricate in HZ. rigidi- 
folia—likewise would tend to indicate that the affinity 
between the two might not be exceptionally close. 
The young leaflets and seedling leaves of Hevea rigid- 
ifolia, asin some specimens of F’rdes 21258, are strikingly 
similar to the adult leaflets of H. pauciflora var. coriacea, 
although the shape and size of the adult leaflets of HZ. 
rigidifolia are peculiar and cannot be easily confused with 
those of any other species. 
In connection with the relationship of Hevea rigidi- 
folia and H. pauciflora var. coriacea, it is pertinent to 
discuss several interesting collections which, in some re- 
spects, would superficially appear to be rather intermedi- 
ate between the two concepts. As stated above, in March, 
1944, Dr. John T. Baldwin, Jr. discovered Hd. rigidifolia 
and introduced it into cultivation (Baldwin in Am. 
Journ. Bot. 38 (1946) 215-216). There is one young in- 
dividual growing vigorously in the collection at the In- 
stituto Agrondmico do Norte (PI. TX). 
Baldwin made chromosome studies in the field and 
prepared herbarium material, but unfortunately there 
appears to be some confusion in the determination of sev- 
eral of his herbarium collections. In two articles (Journ. 
Hered. 388 (1947) 59; Am. Journ. Bot. 34 (1947) 261) 
Baldwin cites his collections 3669 and 3670 as represent- 
ing Hevea rigidifolia. 1 have studied a specimen of 
Baldwin 3670 which is preserved in the Herbarium of 
(119 J 
