54 FARR: QUADRIPARTITION IN SISYRINCHIUM 
course, he had no realization of the internal mechanism of the 
cell. This work was followed by that of Mirbel (17) who 
presented his paper in 1832, though it was not published until 
later. He described and figured quadripartition by furrowing 
in the pollen-mother-cells of Cucurbita Pepo. A little later 
Von Mohl (18) published figures and descriptions of the same — 
process in other plants. It now seems that the interpretation 
given by these first observers was more nearly correct than that 
which has been given by most students of cell-division in higher 
plants in more recent years. 
Up to the present no detailed study has been made of quadri- 
partition in Monocotyledons, and it was with the idea of com- 
paring the situation in this group with that found in Dicotyledons 
that the present study was undertaken. Several cases of 
quadripartition in Monocotyledons are known. In 1915, L. 
Guignard published two papers (12, 13) on the occurrence of 
quadripartition in Monocotyledons. In the first paper he 
includes a comprehensive review of the literature on that subject, — 
as well as on bipartition in the reduction-divisions of Dicotyledons. 
Quadripartition in Monocotyledons and bipartition in Dicoty- 
ledons at the time of reduction-divisions are unquestionably 
the exception in the method of pollen formation in these two 
groups respectively. So rare is their occurrence in fact that 
Van Tieghem (25) used them as characters of prime importance 
in distinguishing the two classes of Angiosperms, thereby 
including the Nympheaceae with the Monocotyledons. Guig- 
nard had previously (11) reported quadripartition in six genera 
of the Orchidaceae, and in the first (12) of his recent publications 
adds four genera (six species) of Liliaceae and six genera (sixteen 
species) of the Iridaceae. To this list the second paper (13) 
contributes three more genera (three species) to the number 
of the Iridaceae having this method. To the Liliaceae may be 
added Strasburger’s (21, p. 151) findings in Asphodelus, and it will 
be remembered that Hofmeister found it in Naias (14, p. 636). 
In 1917, Tackholm and Séderberg published a paper (23) in 
which they discuss tetrad formation in Monocotyledons. In 
addition to its occurrence in the above-mentioned groups they 
refer to quadripartition being reported by Hofmeister in Trades- 
cantia, by Rosenberg in Anthericum and by Von Mohl and others 
in the Juncaceae. So that they find it reported: in six families 
of the Monocotyledons, namely: Liliaceae, Juncaceae, Iridacaea, 
