362 



BOTANY OF THE LIVING PLANT 



encloses a central series, consisting of canal cells (c.c.) which may some- 

 times be very numerous, a ventral-canal-cell (v.c.c.), and the ovum (ov.). 

 At maturity the end of the neck opens in presence of water, owing to 

 pressure of mucilaginous swelling within ; a funnel-like channel then 

 leads down to the ovum (Fig. 304). Spermatozoids, motile in the water, 

 may be seen to enter it, and there is reason to believe that their move- 

 ments are directed by diffusion 

 from it of some soluble sub- 

 stance, such as cane sugar. 

 In essentials the process is as 

 in Peridophytes, but there is 

 marked difference in the details. 

 The result of fertilisation is 

 the Sporogonium (Fig. 296, p. 

 354). It usually appears as 

 a radially constructed body, 

 seated in the tissue of the 

 Moss Plant, and bearing at the 

 end of a long stalk (seta) a more 

 or less oval head (the capsule), 

 which at ripeness contains very 

 numerous spores. It is covered 

 at first by a hood or cap 

 (calyptra), which falls off at 

 maturity, disclosing a lid, or 

 operculum. This finally separ- 

 ates by a transverse split, and 

 falling away opens the capsule, 

 just as the lid might be taken 

 off a covered jar. In most 

 Mosses a fringe of ragged fila- 

 ments, the peristome, is thus 

 disclosed, which by their hygro- 

 scopic movements serve to distribute the dry and dusty spores 

 (Fig. 308). The sporogonium is usually green while young, but 

 yellowish or brown when ripe. This is due to photo-synthetic tissue, 

 which is specially developed at the enlarged base of the capsule 

 (apophysis), where also stomata may be found, providing for ventila- 

 tion (Fig. 305). But such tissues dry up at maturity, so that the 

 capsule is then full of the yellowish spores. 



The sporophyte thus constructed differs from all the sporophytes 



- 5 



FIG. 305. 



Median section of an immature sporogonium 

 of Funaria. s=seta. ap. = apophysis. w= water 

 storage tissue. s/.=stomata. sp. s.=spore-sac. 

 arch. = archisporium. co/=columella. p = peristome. 

 op= operculum. Based on a drawing by Haber- 

 landt. (x2o.) 



