Nichols, A morphological study of Juniperus communis var. depressa . 209 
They possess a rather coarse reticulnin and have a distinct nucle- 
olus. The development of resting nnclei at the close of the hetero- 
typic division has been described in Larix (Strasburger 1900), 
Taxodium (Coker 1903b), Pinus (Ferguson 1904), Juniperus 
(Noren 1907), and Thuja (Lewis 1908). 
Düring the telophase (fig. 30) the spindle übers are con- 
spicuous as a barrel-shaped mass extending between the two daughter 
nuclei, and in many cases thickenings of the übers in the equatorial 
plane give indications of an ephemeral cell plate, such as occurs 
in Larix (Strasburger 1895), and occasionally in Pinus (Fer¬ 
guson 1904). Coker (1903b) reports that in Taxodium a cell 
plate is produced which extends entirely across the cell and persists 
throughoüt the second division. In Juniperus, however, the cell 
plate entirely disappears before the initiation of the homotypic 
division. 
In the brief period of rest which succeeds the heterotypic 
division the daughter nuclei grow considerably in size, but within 
a short time the üner meshes of the reticulum are again drawn in, 
and a coarse, more or less anastomosing structure is produced 
which gives rise to the chromosomes of the homotypic division. 
If a spirem is formed, it is poorly deüned and irregulär. The 
spindles of the ürst division now disappear, new spindles are formed, 
and the nuclear membrane is lost sight of. As in the previous 
division, the chromosomes become oriented at the equator (üg. 32), 
longitudinal Splitting takes place, and the granddaughter chromo¬ 
somes are drawn toward their respective poles (ügs. 33, 34) where 
the Organization of the granddaughter nuclei is brought about. 
The nuclei thus formed are at ürst very small — about 7 p in 
diameter — with a reticulum consisting of granulär masses of 
chromatin united by üner Strands. 
As noted by Coulter and Chamberlain (1901) in Pinus, 
the division just described may be either tetrahedral or bilateral 
(ügs. 33, 34). The former method is more prevalent, but bilateral 
division is of frequent occurence. The successive development of 
different microspore mother cells in the same sporangium, observed 
by these authors and others in various conifers, is very noticeable 
in Juniperus , especially during the stages intervening between 
synapsis and the formation of tetrads where one step follows another 
with comparative rapidity (üg. 11). The sporangia at the apex 
of a cone are invariably further along in their development than 
those at the base. 
Development of the microspores. — Miss Ferguson 
(1904) has made some very interesting observations in connection 
with the formation of the microspores in Pinus. She ünds that 
“the wall of the microspore mother-cell increases markedly in 
thickness, and its protoplasmic contents is separated into four com- 
partments by prominent cross walls which are continuous with the 
inner portion of the mother-wall. The microspores are then de- 
veloped, each in its own particular chamber of the mother-cell.” 
Noren (1907) reports that in J. communis a division of the 
Beihefte Bot. Centralbl. Bd. XXV. Abt. I. Heft 2. 14 
