Revision of Genus Alstonia — MONACHINO 
Literature: No work of monographic char- 
acter on the genus Alstonia has hitherto been 
attempted. Taxonomic treatments have been 
of a local nature and are found principally in 
regional or general floras. An example of such 
treatments is Hooker’s flora of British India 
(1882: 630, 641-643). The species of the 
Malay Peninsula are presented in excellent 
style in King and Gamble’s flora of the Malay 
Peninsula (1907). Four of these species are 
also described by Pitard in Le Comte’s Flore 
Generale de I’lndo-Chine (1933: 1161-1166). 
Comments on certain species from China appear 
in Tsiang’s Notes on the Asiatic Apocynales 
(1934, 1936). Koorders and Valeton’s Bij- 
drage No. 1 tot de Kennis der Boomso orten 
van Java (1894: 115-125) and Miquel’s Flora 
Indiae Batavae (1856: 436-440) refer to 
species of Alstonia in Java. The species found 
in New Guinea are interpreted by Markgraf 
(1927). Bentham’s Flora Australiensis (1869: 
312-315) deals with the Australian represen- 
tatives of Alstonia. There is no single taxonomic 
treatment of all the species known from New 
Caledonia, but 11 are cited by Spencer Moore 
( 192 1 : 362-364) of which five are described 
as new. Guillaumin (1911^: 195-196) cites 
13 species and Schlechter (1906: 235-237) 
cites seven species. The account of Alstonia 
in Samoa given by Christophersen (1935: 
177-180) and other reports, by various authors, 
on the genus in the Pacific islands or in Africa 
are of importance only for individual species. 
Of works other than taxonomic, J. K. Santos’ 
Histological Study of the Bark of Alstonia 
scholaris R. Brown from the Philippines is of 
particular interest. H. H. Janssonius (1926: 
610-626) treats the wood anatomy of A. 
scholaris, A. spectabilis, A. angustiloba, and 
A. spatulata and presents a key to these species 
based on wood structure (1925: 576). The 
lightweight wood of A. spatulata is discussed 
by E. Graffe (1934). 
Chemical and physiological studies of ex- 
tracts of A. scholaris are presented by R. F. 
Bacon (1906: 1008-1019). Here references 
135 
are made to earlier workers who have investi- 
gated Alstonia for its therapeutic and chemical 
properties. Noteworthy among these are Jobst 
and Hesse, Gorup-Besanez, Gruppe, and Har- 
nack. The first four of these authors are cited 
by Santos, who, in addition, cites Dymock and 
Fltickiger and Hambury. 
Recently, Pichon (1947) wrote a very in- 
teresting paper on Alstonia. His article is dis- 
cussed in the Supplement following the body 
of the present treatise. Pichon suggested that 
the Central American-Mexican Tonduzia is 
truly an Alstonia. The seeds of Tonduzia, how- 
ever, are not ciliate as in Alstonia but finely 
membranously lacerate along the margins. 
System of arrangement of material: In the 
taxonomic portion of this paper, the key to the 
sections, diagnoses of the sections, and the keys 
to all the species and varieties immediately 
follow the description and discussion of the 
genus. Secondary sectional characters are given 
in the body of the paper preceding the treat- 
ment of the individual species belonging to the 
section. For full characterization of each species 
it is necessary to read the individual descrip- 
tion, and also the secondary sectional gen- 
eralizations heading the group, as well as the 
original diagnosis of the section. 
In the treatment of the species reference 
is made only to those illustrations which were 
available and, in the writer’s opinion, signifi- 
cant; a complete survey of illustrations or of 
the bibliography was not attempted. Not all 
specimens examined in the well-represented 
species are cited. 
In order to save space, the citation of her- 
baria is generally limited in the following 
fashion: If the specimen is deposited at the 
New York Botanical Garden no indication is 
made of herbaria where it is deposited. If the 
collection is not represented here but is repre- 
sented at the Arnold Arboretum, then that in- 
stitution is cited exclusively. If not in either 
the Arnold Arboretum or the New York Bo- 
tanical Garden but present in the Gray Her- 
barium the latter only is cited. If not in any 
