1267 
The foliage dies down in summer but comes up again in 
early spring or late Winter, where the climate is mild. 
Apparently withstands zero temperatures ; Collected in 
pockets of humus soil beneath tall trees on a rocky 
mountain slope at an elevation of over 2,000 feet above 
sea level. May possibly be hardy at Washington, D.C." 
(Meyer. ) 
Malus theifera (Malaceae), 45681. Prom Jamaica 
Plain, Massachusetts. Presented by the Arnold Arbore- 
tum. A small handsome tree with stiff spreading 
branches, resembling a cherry tree when in bloom. The 
fragrant flowers are white or light pink, with purple 
calyx, and the "young leaves are purplish. The fruit is 
globose, light greenish yellow with reddish cheek, 
ripening in Massachusetts in October. The tree is A- 
siatic in origin, ranging from China to Assam. (Adapt- 
ed from Rehder, and also Bailey, Standard Cyclopedia 
of Horticulture, p. 2872. 
Pavetta zimmermanniana (Rubiaceae), 45554. Prom 
Buitenzorg, Java. Presented by . the Director of the 
Botanic Gardens. A small rubiaceous tree or shrub, 
with opposite, nearly elliptic leaves and clusters of 
small, slender-tubed white flowers. "The remarkable 
researches of Zimmerman and Paber, detailed in the 
Jahrbucher fur Wissenschaf tliche Botanik, vol. 51, p. . 
285, 1912, and vol . 54 , p. 243 , 1914 , make this species 
of unusual interest. Paber has proved that the leaves 
of, this and several other species of Pavetta, Psychot- 
ria, and possibly other genera of the . Rubiaceae con- 
tain colonies of a non-motile, nitrogen-fixing bacte- 
rium which he names Myeo- bacterium rubiaeeamm. The bacte- 
ria of this species almost invariably inhabi t the mi - 
cropyle of the young seed and, when the seed germinates, 
grow through certain stomata of the very young leaves 
and into the intra-cellular spaces formed in the leaf 
tissues around these stomata. Cavities "are formed 
through the growth of the epidermal cells which later 
close entirely and make bacterial nodules which are 
deeply imbedded in the leaf tissues. A single leaf 
may have several dozen of these symbiotic bacterial 
nodules. Faber was able, by treating the seeds with 
hot water and a solution of sublimate to kill the in- 
habiting myco-bacterla and, later, to infect part of 
the seedlings grown from these seeds with pure- cultures 
of the bacterium. The artificially infected seedlings 
grown in soil free from combined nitrogen, grew well 
