214 Nichols, A morphological study of Juniperus communis var. depressa. 
For a time the further growtb of tlie pollen tube toward the 
female gametopbyte proceeds yery slowly, so tbat four weeks later 
it bas penetrated scarcely more tban a tbird of tbe distance from 
tbe tip of tbe nucellus to tbe embryo sae. Simultaneonsly witb 
tbe appearance of tbe arcbegonium initials in tbe female pro- 
tballium, bowever, tbe pollen tube commences to force its way 
rapidly tbrongb tbe nucellar tissue, crusbing and disorganizing tbe 
cells of tbe nucellus witb wbicb it comes in contact, and in a few 
days enters tbe arcbegonial cbamber wbere its tip presses up close 
to tbe arcbegonium complex (fig. 91). Lawson (1907 b) States tbat 
in tbe Cupresseae tbe contents of tbe various tubes are discbarged 
into a common arcbegonial cbamber. Wbile tbis may be true in 
some cases for J. communis, repeated observations of instances 
wbere more tban one pollen tube bave entered tbe arcbegonial 
cbamber sbow tbat as a rule tbe male elements continue to be 
enclosed in tbeir respective tubes nntil tbe discbarge of tbe male 
cells into tbe egg. Tbrougbout tbe period wbicb bas just been 
described tbe body cell and tbe two vegetative nuclei are found 
close .togetber near tbe lower end of tbe tube (figs. 48—51). 
Tbe stalk and tube nuclei enlarge somewbat and become so nearly 
alike tbat it is impossible to distinguisb one from tbe otber, wbile 
tbe body cell increases enormously in size and, just previous to 
tbe formation of tbe male cells, attains a diameter of about 60 y. 
Tbe presence of a distinct delimiting membrane abont tbe 
body cell in gymnosperms was apparently first noted by Hof¬ 
meister (1851) in Juniperus sibirica. It bas since been described 
in J. communis by Belajeff (1893), Noren (1904, 1907), and 
Sludsky (1905), and appears to be a cbaracteristic feature in all 
tbe Cupresseae tbns far stndied. A similar structure is found 
among tbe Taxeae, and in Sequoia. Among tbe Podocarpeae, on 
tbe otber band, a membrane is present about tbe young body cell 
of Bacrydium (Young 1907), but soon disappears, wbile sncb a 
structure is apparently entirely absent in Podocarpus (Coker 1902), 
Saxegothaea (Noren 1908), and Pliyllocladus (Kildabl 1898). 
Among tbe Abieteae tbe body nucleus is surrounded only by a 
dense zone of cytoplasm wbicb may include also tbe stalk and 
tube nuclei. In tbe cycads and Gingko a membrane is always 
present. 
Tbe demonstration of blepbaroplasts in tbe body cells of tbe 
Gingkoales and Cycadales suggested tbe possibility tbat some traces 
of cilia-forming Organs migbt exist among tbe Coniferales and 
Gnetales. A careful study, bowever, of a large ’number of body 
cells in J. communis depressa, in all stages of development, bas 
failed to reveal any structures wbicb appear to be definitely bomo- 
logous witb blepbaroplasts. As in tbe otber Cupresseae , tbe body 
cell is densely packed witb starcb. A radiate structure of tbe 
cytoplasm bas been described by Coker (1903 b) in Taxodium, 
and by Noren (1907) in J. communis, but bas not been observed 
by tbe writer. 
