ne 
1899] OOGENESIS IN PINUS 275 
higher plants, especially by Cavara’s and very recently by 
Duggar ®, 
Ikeno’s? figures and description of Cycas revoluta, while not 
dealing with details in the development of the nucleus of the 
oosphere, nevertheless indicate that the sequence is about as I 
have described it for Pinus. Blackman’s recent work on Pinus 
yluesiris will be considered later. The staining reactions do not 
seem to furnish a reliable method of distinguishing chromatin 
nucleoli from other spherical bodies. In thin sections some 
nucleoli show a sharp differentiation into an outer deeply stain- 
ing portion and an inner part which stains lightly (jg. 29). 
Fig. 28 shows a peculiar case. There seemed to bea crack in 
the nucleolus, and upon applying a gentle pressure the central 
portion came out from the shell. It might be suggested that the 
besence or absence of this outer portion, or, when present, its 
relative thickness, may account in some measure for the reaction 
‘ostains. That the staining does not identify chromatin nucleoli 
shown by the fact that many of the “nucleoli” in the proteid 
vacuoles stain intensely black with iron-alum-hematoxylin, blue 
with cyanin, or red with safranin. 
FERTILIZATION. 
‘Sree ll figure of Picea shows conjugating nuclei of 
Pi 5a According to Coulter?, one of the male nuclei in 
omnia its entrance into. the oosphere, pene ae a 
Mica _ t ig moment of fusion, it is as large as sa female pr 
» dn Ikeno’s figures of Cycas, and Blackman’s * of Pinus 
ian rs / : 
aV18, & <= a 
B tytn Be isc: of the poll in and embryo sac in Bignonia venusta. 
ull Torr, Bot, Cin £35: ioe ae a 
5 
bei Cycas ke der Geschlechtsorgane und den Vorgang der Befruchtung 
. : rb. £. wiss. Bot. 32:557-602. 1898. 
lcune strutture nucleari. Atti del R. Istituto Botanico dell ’Univer- 
1897. 
*Not : : 
1899, * OM the fertilization and embryogeny of conifers. Bot. Gaz. 23 + 4043+ 
i 
On t ‘ pe 4 
Petry Pa logical features of fertilization and related phenomena in Pinus ” 
Fans. Roy. Soc. of London. B. 190: 395-426. 1898. 
