. Elementary botany . ^AreH Fig. 272. Last division of the egg in the white pine cutting off the ventral canal cell at the apex of the archegonium. End, endosperm; Arch, archegonium. theridium. there being no wall formed. The sperm mother cell also passes down the tubular sac, and divides again into two sperm cells, as shown in fig. 270. About this time, or rather a little earlier, with the pollen tube part way through the nucellar cap, winter overtakes it, and all growth ceases until the following spring. 426. Fertilization.—In the spring the advance of the pollen tube con- tinues, and it fin
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