My good friends, the Rev. Mr. and Mrs. William 
Arlie Ross have devoted their almost limitless energies 
and enthusiasm for over fifteen years to educational and 
missionary work amongst the poor inhabitants of the up- 
per Rio Negro. Their home and school, located at Jucabi 
at the mouth of the Rio Curicuriari, has always been 
open to travellers and scientists. In gratitude for their 
kindnesses and help during my explorations in 1947-48 
and in respect for their self-sacrificing spirit, I have taken 
the liberty of naming this most extraordinary tree in 
their honor. 
Several years ago, I prepared a manuscript synopsis 
of the genus Micrandra as known from the then avail- 
able herbarium material, which was not extensive. Be- 
cause of pending field work which offered an opportunity 
of visiting the type localities of several of the concepts, 
this manuscript was not published. During the prepara- 
tion of the synopsis, I examined specimens of Ducke 
1560, which had been filed in our herbaria as Micrandra 
siphonioides Benth. Impressed with the clear differences 
between the capsule of Ducke 1560 and that of true Mi- 
crandra siphonioides, 1 drew up a description of the 
Ducke collection as an undescribed species of Micrandra 
and annotated the sheets with a new binomial referring 
to the elongate shape of the fruit. There were also dif- 
ferences in the leaves, and these differences enabled me 
to annotate the sterile collection Allen 3109 with the 
same name. ‘There was never the slightest doubt in my 
mind that the specimens belonged in the genus Micran- 
dra, even though flowering material was not available. 
During my year’s sojourn in the upper Rio Negro 
basin in 1947-48, it was possible to collect, from several 
widely separated localities, very abundant material of 
this concept in flower and in fruit. I happened upon the 
first tree by noticing the very coriaceous leaves scattered 
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