1896] CURRENT LITERATURE 507 
F. DELPINO has just published “a discussion upon the classification of 
monocotyledons, based upon certain new criteria. A review by Solla*s fur- 
‘nishes the basis for the following statement of his views. Engler’s classifica- 
tion* of 1892 has seemed to morphological taxonomists to be by far the 
most natural one yet proposed, and it remains to be seen whether Delpino 
has proposed anything better in the way of natural grouping. He recog- 
_ hizes the two monocotyledonous groups, the eucyclic (trimerous pentacyclic 
floral structure) and the polycyclic (unstable floral structure and varying 
number of whorls). The eucyclic monocotyls are not regarded as primitive, 
but as derived from the polycyclic groups, which are believed to be the 
“connecting link” between eucyclic monocotyls and dicotyls. In both the 
monocotyl groups there are forms which have retrograded, giving rise to 
four taxonomic groups, viz., normal and reduced polycyclic forms, and nor- 
mal and abnormal eucyclic forms. 
The group of “normal polycyclic monocotyls” includes Alismacez, 
Butomacee, and the higher genera of the Hydrocharidee. The author 
makes the Butomacez his starting point, and considers Butomus umbellatus 
_ tobe the oldest form, because it resembles several polycyclic dicotyls. Con- 
fected with these is the group of ‘reduced polycyclic monocotyls,” which 
includes the lower Hydrocharidee, Juncaginee, Aponogetonacez, Potamo- 
§etonacez, and Naiadacez. 
The “eucyclic monocotyls” include all the rest of the families with penta- 
Cyclic structure. The nectary furnishes a biological and phylogenetic char- 
acter by which they are subdivided into three groups: the Anadenten, which 
have no nectaries; the Carfadenten, which have nectaries in connection with 
’ the Carpels; and the Peta/adenien, which have nectaries in connection with 
the floral leaves. 
Discs oe 
The author regards the leaves as of taxonomic value in large groupings. 
“ese groups are as follows : (1) those with sword-shaped leaves, subdivided 
to Gladiate and Hemigladiate ; (2) those with three-sided leaves, all of 
ch may be derived from the genus Dracena; (3) those with ligules 
Graminew, etc.) 
It will be noted that Delpino, like Engler, makes two groups of mono- 
otyls, but only the Helobie are regarded as polycyclic, all the rest being 
y 
“a 
' “*Mem. Real. Accad. Sci. Bologna V. 6 : 83-116. 1896. 
"5 Bot. Centralb, 67 : 370. 1896. 
“Die systematische Anordnung der monokotyledoneen Angiospermen : Abhandl. 
mig. Preuss, Akad. Wissen. Berlin, 1892. 
