524 



HUTCHINSON'S POPULAR BOTANY 



chaete, popularly but incorrectly known as the "flower" of the Moss. These 

 " flowers " are of three kinds : first, containing antherids only ; second, con- 

 taining archegones only ; and third, containing both antherids and 

 archegones. Sometimes these occur on the same plant, in some species on 

 different plants. Where the sexes are thus separated the plant is said to be 

 dioecious, where the two sexes are on the same plant the latter is monoecious ; 

 and when one u flower " contains both antherids and archegones it is her- 

 maphrodite. The male flower (perigone) may be distinguished by its 

 broader and thicker leaves. Among the sexual organs are a number of 

 thread-like or club-shaped bodies known as paraphyses. The antherid when 

 mature consists of a foot-stalk bearing a club-shaped (sometimes spherical) 

 head, which opens at the apex or splits down the sides, freeing a large 

 number of minute cells, in each of which is coiled a long antherozoid, 



tapering forwards, at 

 which extremity it is pro- 

 vided with two long cilia 

 (fig. 663). The anthero- 

 zoids swim about in the 

 mucilaginous fluid which 

 accompanies their expul- 

 sion and make their way 

 to the archegones. The 

 latter consist of a swollen 

 basal portion, in which is 

 the oosphere, and a long, 

 slender neck, pierced by a 

 canal, the mouth of which 

 is guarded until maturity 

 by a couple of lid-cells 

 (the stigma). At maturity, 

 a quantity of mucilage being ejected from the canal, the lid-cells are forced 

 apart, and the way is open for the entrance of the antherozoids. As a 

 rule, only one oosphere in a " flower" is fertilized and becomes an oosperm. 

 This develops into the sporogone or asexual generation, which, until it 

 perishes, always remains attached to the sexual generation and is 

 nourished by it. The growth of the sporogone ruptures the arche- 

 gone transversely and stands revealed as the stalked capsule of the 

 Moss containing the spores. The remains of the ruptured archegone 

 become the vagine or sheath below the capsule, and the calypter or cap 

 above it. This calypter is, as a rule, of very thin, chaffy material, and is 

 thrown off by the expansion of the capsule, much as the similar bud-scales 

 are thrown off by the expansion of the buds of trees and shrubs in spring. 

 In the Common Hair Moss (Polytrickum) the calypter is thick and shaggy, 

 consisting of long hair-like scales of a pale golden hue, which makes the 



FIG. 668. Plagiochila asplenioides, A SCALE Moss. 



The general character of these plants is here shown the creeping stem 



with its delicate leaves arranged in one plane, and the terminal fruits, one 



intact and the other after it has burst to discharge its spores. 



