226 WILSON EXPEDITION TO CHINA 
SUBGENERIS CERASI SYSTEMA NOVUM. 
This subgenus can be divided in two very natural groups: 
Grex I. TYPOCERASUS. Gemmae supra quamvis folii cicatricem solitariae, 
hae floriferae, illae ramum foliatum promittentes: plantae triaxiflorae. (Gemmae 
saepe in ramis abbreviatis confertae.) Petioli longiusculi v. longi. 
If, as usual, the branch of the previous year is considered as axis I., the axis of 
the bud or of the inflorescence will be axis II., exactly as in the subgenus Padus, 
while the pedicel itself, even if the inflorescence is reduced to one flower, is to be 
called axis III. The plants therefore are tri-axial. 
In such a polymorphous group as Cerasus it is not surprising that transitional 
forms occur. Thus I have observed in P. stipulacea and P. microlepis occasional 
ternate buds after the type of Microcerasus. Both species, however, belong 
according to their other characters to T'ypocerasus. 
Grex II. MICROCERASUS. Gemmae sub florationis tempore typice ternae, 
media typice ramum foliatum promittens (saepissime vero abortiva), laterales 
floriferae; plantae quadraxiflorae. Petioli insigniter breves (exc. in P. pumila 
affinisbusque, ubi petioli longiusculi). 
The two lateral buds originate in the axils of the lowest pair of scales of the 
middle bud, their axes, therefore, become axes of the third order, while the pedi- 
cels will be axes of the fourth order. The plants, therefore, are quadri-axial. 
Grex I. TYPOCERASUS.! 
BepalafefeXH. . [| 2.4 20 X 0 Ce Sect. 1. CREMASTOSEPALUM. 
Sepala erecto-patula v. rarius patentia (sed cf. P. cerasoidem, ubi sepala interdum 
reflexa videntur) 7. 12 1 a Sect. 2. PSEUDOCERASUS. 
Sect. 1. CREMASTOSEPALUM. 
Foliorum dentes obtusae v. rotundatae v. emarginatae, glandula saepissime oblique 
v. basaliter juxta dentem sequentem inserta v. rarius apicali. 
Dentes brevissimae. Involucrum (i.e. inflorescentiae perulae basales) ante 
anthesin deciduum. (Europa, Asia occidentalis, America borealis.) 
Subsect. 1. MAHALEB. 
Folia suborbicularia. Petala glaberrima.  Drupa nigra v. sordide lutes- 
cens, (Europa, Asia occidentalis.) . . . . .... Ser. 1. EUMAHALEB. 
Folia longiora angustiora. Petala extus pilosa, nonnisi in P. emarginata 
glabra. Drupa rubra. (America borealis.) . . . Ser. 2. PARAMAHALEB. 
Dentes bene evolutae. Involucrum sub anthesi arcte adhaerens magnum Y. 
majusculum. (Europa, Asia occidentalis.) . . . Subsect. 2. EUCERASUS. 
Foliorum dentes acutae v. acuminatae v. subito brevissime cuspidatae glandula 
apicali. 
Petala haud emarginata. 
Bracteae herbaceae saepe majusculae, sub fructu persistentes. Flores coae- 
tanei. 
Racemi breves v. longiusculi, (3-)4-9-flori, densi- v. laxiflori, pedunculati. 
(China, Japonia usque ad terram Amurensem et insulam Saghalin.) 
Subsect. 3. PHYLLOMAHALEB, 
! Several species of which the flowers are not known can be referred to certain 
groups only according to their general character. Therefore a revision of these 
species will be necessary when complete material is available. 
