1004 
In the opinion of Professor Pittier the origin 
of the Cuna-Cuna has to be looked for elsewhere 
than in the interior of Colombia, and the Guaymies, 
Valientes, Bribri, Térrabas, Sumos, ete., are more 
likely to be the remnants of a primitive autoch- 
thonous stock. Pittier’s talk was illustrated by 
numerous lantern slides and the exhibition of the 
objects colleeted among the Chocoes and Guaymies. 
TRUMAN MICHELSON, 
Secretary 
THE BOTANICAL SOCIETY OF WASHINGTON 
THE 81st regular meeting was held at the Cosmos 
Club, May 7, 1912, at 8:00 p.m. President W. A. 
Orton presided. Twenty members were present. 
The following papers were read: 
Further Studies on the Pecan ‘‘Rust’’: F. V. 
RaNpD. 
A preliminary report on the fungus causing this 
pecan leaf disease was published in Phytopathology 
for August, 1911, under the name Mycospherella 
convexula. Since that time the fungus in question 
has been obtained from a number of other sources 
and several strains known to have originated from 
single two-celled ascospores have been under study. 
In the course of one and one half year’s growth 
in culture, strains originally producing a majority 
of apparently two-celled ascospores have gradually 
changed, until now most of the ascospores are dis- 
tinetly non-septate. Furthermore, a typical Gloe- 
osporiwm form was developed in culture and also 
obtained from the host. A large number of col- 
onies known to have originated from single asto- 
spores or single conidia all gave cultures pro- 
ducing both perithecial and conidial forms, show- 
ing the two to be different phases in the life cycle 
of the same fungus. Inoculations on Jonathan and 
Yellow Newton apples gave a decay similar to 
bitter-rot, with production of conidia and imma- 
ture perithecia on the latter. Inoculations on 
young pecan leaves under greenhouse conditions 
gave negative results, but infections together with 
production of conidia and mature perithecia, 
readily occurred on living leaves in a damp cham- 
ber. From the studies summarized above it would 
appear that the fungus is closely related to if not 
identical with Glomerella rufomaculans, and that 
it is not a very active parasite on the pecan. 
Distribution of Pigment in the Seed-coat of the 
Cowpea: Dr, ALBERT MANN. 
Transverse sections of the seed-coat disclose 
three principal layers of cells: an outer palisade 
SCIENCE 
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[N.S. VoL. XXXV. No. 915 
layer, a heavy-walled layer below this of empty 
cells, and a layer of considerably compressed cells 
with long axis parallel to the surface of the cow- 
pea. 
It was found that the colorations in the cowpea 
are the result of pigments deposited in two of 
these layers. In all colored cowpeas there is a 
basal color or practically uniform tint and in- 
variably to be found in the lowest of the three 
layers, which the speaker terms the basal color 
layer. This is a melanin compound of an orange- 
yellow tint, grading into lemon-yellow and pale 
buff. All other colors are obtained by superposing 
upon this basal color layer various pigments, and 
these are uniformly deposited in the palisade cells, 
and as a rule in the lower and larger third of the 
cell cavity. Three colors are found here: black 
to blue-black, or sometimes purple tint, which is 
an anthocyanin, a yellow or brassy-brown pigment 
and an intense black pigment, the last two being 
melanin compounds. By various arrangements of 
these three superposed tints in the palisade cells, 
or by the absence of any pigments in these cells, 
the various schemes of coloration in the cowpea 
are obtained; the marbling, blotching, dotting, as 
well as the uniform colors of some cowpeas, being 
produced by the basal color plus such superposed 
arrangements of color in the palisade cells as are 
characteristic of the different varieties. 
In the case of the few cowpeas having white or 
colorless seed-coats, the result is obtained by the 
suppression of all pigments both in the basal color 
layer and in the palisade layer. 
A wild cowpea secured from North Niveria, 
Africa, is of particular interest, in that upon the 
same cowpea all the elements of color, as well as 
all the schemes of coloration are to be found. 
The Purpling Chromogen of the Hawaiian Bitter 
Yam: H. H. BARtLert. 
Tilustrations of the Phytogeography of the North 
American Continent: Dr. JOHN W. HARSH- 
BERGER (by invitation). 
~The speaker displayed to the society an album 
of twelve volumes of photographs and illustrations 
of North American vegetation, collected during 
the preparation of his recently published work on 
the phytogeography of North America. The source 
of the material and method of preparation and 
classification were discussed, and the general plan 
and seope of the work were explained in detail. 
W. W. STOCKBERGER, 
Corresponding Secretary 
