302 



BOTANY UK THE LIVING PLANT 



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

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

 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 

 IVIoss 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). P)ut such tissues dry up at maturity, so that the 

 capsule is then full of the yellowish spores. 



'Ilie sporophytc thus cons(nicted difiers from all the sporophytes 



I-IG. 305. 

 Median section oi an immatLn-c sporogonium 

 of Funana. 5 — seta. a^. — apophysis, sw — water 

 storage tissue, s/.— stomata. sp. s. — spore-sac. 

 flrc/i. = archisporium. co/ = columella. ^ — peristome, 

 o^^operculum. Based on a drawing by Haber- 

 landt. (20.) 



