1003 
to 50 feet high and 1| to 3 Inches In diameter. Re- 
ported to have a wide range in Africa. This species 
has a very different appearance from the remainder of 
the genus, but the structure of the splculae in all 
the species is very similar. For technical descrip- 
tion see Colonel Munro ' s Monograph of the Bambusaceae, 
in the Transactions of the Llnnean Society, London, 
Vol. 26, p. 127, 1870, 
Paulownia duclouxii Dode . (Scrophularlaceae . ) 42693. 
Plants from Paris, France. Purchased from Messrs. 
Vilmorin-Andrieux & Company. A recently introduced 
tree from Yunnan, China, differing from the common 
Paulownia in its white flowers, slightly rosy, and 
without spots. Flowers at the end of winter before 
the leaves appear. 
Pavetta zimmermanniana Valet. (Rubiaceae.) 42767. 
Seeds from Buitenzorg, Java. Presented by Dr. J. C. 
Koningsberger , Director Botanic Gardens. A small 
rubiaceous tree or shrub, with opposite, nearly ellip- 
tic leaves and clusters of small, slender-tubed white 
flowers. "The remarkable researches of Zimmerman and 
Faber detailed in the Jahrbiicher fur wlssenschaf tliche 
Botanik, vol. 51, p. 285, 1912, and vol. 54, p. 243, 
1914, make this species of unusual interest. Faber 
has proven that the leaves of this species of Pavetta 
and of several others of this genus as well as of the 
genus Psychotria and possibly other genera of the 
Rubiaceae contain colonies of a nitrogen-fixing bac- 
teria which he names Myco-bacterium rubiacearum . The bac- 
teria of this species inhabit almost invariably the 
micropyle of the young seed and when it germinates, 
although not a motile form, grow through certain 
stomata of the very young leaves and into the intra- 
cellular spaces formed by the leaf tissues around these 
stomata. Reacting one on the other, there are formed 
through the growth of the epidermis cells cavities 
which later close entirely and make bacterial knots 
which are deeply Imbedded in the leaf tissues . A single 
leaf may have several dozen of these symbiotic bac- 
terial knots. Faber was able by treating the seeds 
with hot water and sublimate solution to kill the in- 
habiting myco-bacterla and later Infect part of the 
seedlings grown from their seeds with pure cultures 
of the bacterium. The artlflcally Infected seedlings 
grown in soil free from combined nitrogen grew well 
and remained healthy for four months whereas those 
