26 BULLETIN 119, U. S. DEPARTMENT OF AGRICULTURE. 
THE URD, OR BLACK GRAM. 
The urd, or black gram (Phaseolus mungo L.; Pl. VI), is very similar 
to the mung and the botany of the two has become much confused. It 
is easily distinguishable from the mung, however, by the much shorter, 
stouter, very hairy pods and larger oblong soe which vary in 
color ian blackish to olive. The flowers are fully selfifortile. It is 
- cultivated only in India. According to Mollison (1901, p. 88) an area 
equal to about 250,000 acres is devoted to this crop in the Bombay 
Presidency, and Duthie and Fuller (1882, p. 39) say that the area in 
the Northwestern Provinces and Oudh is about 260,000 acres. 
In botanical characters the urd is very similar to the mung, but 
in habit the plants are lower and spreading, the branches usually 
‘procumbent. The very hairy stems are never twining in any variety 
grown at Arlington farm, but a twining variety occurs in India and 
is distinguished as a crop under the name “‘tikari.”’ 
There is still room for slight doubt regar ding the botanical name 
to be applied to the urd. There is no specimen labeled Phaseolus 
mungo in the Linnean herbarium. Prain (1897, p. 423) points out, 
however, that Linnzus’s description of Phaseolus mungo accords 
better with the tikari than with any related species, and his judg- 
ment, based on a wide knowledge of the Indian species, can hardly 
be controverted. 
From the standpoint of a forage or cover crop the urd is inferior 
to the mung, as it makes much less herbage. The. pods, however, 
do not shatter so readily, so little of the seed is thus lost. Owing to 
the low, spreading habit, however, it is necessary to pull the plants 
in harvesting. The best yield of seed at Arlington farm was 13.6 
bushels per acre from No. 17308. The average yield in India was 
stated to be about 7 bushels per acre in 1912. 
The urd is utilized as a green-manure crop in Trinidad under the 
name of ‘‘woolly pyrol,’’ and wherever Hindoo laborers are numerous 
in the West Indies they cultivate this plant for food. 
In warm, moist weather the urd is much subject to mildew (Ery- 
siphe polygont). It is also affected by both the leaf-spots that 
attack the mung and the cowpea. 
The habit of the urd is such that it can not be as easily harvested 
for hay or seed as the mung. It is difficult to see wherein it can 
compete as a forage crop under American conditions with either the 
cowpea or the soy bean. As human food the seeds seem far less 
desirable than other species. 
INTRODUCTION. 
One variety of the urd, erroneously named Dolichos cultratus, was 
grown in Louisiana in 1898 (Dodson and Stubbs, 1898, p. 37). It 
was early enough to mature and shatter its seeds by September 1, 
so that when it was plowed under a good second crop was produced. 
