LESS. XXX PROTONEMA 407 



a', a sperm-cell with enclosed sperm : A'*, a free-swimming sperm. 

 ( X 800. ) 



B^, an ovary of Funaria, surface view, showini; venter {v) and neck 

 {«) : B^, the same in optical section, showing ovum (ov) and canal cells 

 {en. c) : B'', the same after disappeari.iice of the canal cells : the neck is 

 freely open, and the ovum {ov) exposed. ( x 200. ) 



c^, ovary with withered neck containing an embryo {spgn/n) in the 

 polyplast stage ( x 200) : in c ' the ovary, consisting of swollen venter [v) 

 and shrivelled neck («), encloses a young sporogonium (spptnt) ; the 

 distal end of the stem is shown with bases of leaves (/) ; in c^ the venter 

 has ruptured, forming a proximal portion or sheath and a distal portion 

 or calyptra which is carried up by the growth of the sporogonium. 

 (X 10.) • 



c*, a small plant of Funaria with ripe sporogonium consisting of seta 

 (j/), with urn (it) and lid (/) covered by the calyptra (c). 



c', diagrammatic vertical section of urn {«), showing lid (/), air spaces 

 {a), and spores (s/>). 



d', a germinating spore of Funaria, showing ruptured outer coat (jr/) 

 and young protonema {pr) with rhizoid (rk). ( x 550.) 



D ', portion of protonema of the same, showing lateral bud (id), from 

 which tlie leafy plant arises. ( x 90.) 



(a and D, after Sachs ; B, c*, and c*, altered from Sachs.) 



dilates : the embryo has now become a sporogonium^ con- 

 sisting of a slender stalk (c*, si) bearing a vase-like capsule 

 or urn {u) at its distal end. In the meantime the elonga- 

 tion of the stalk has caused the rupture of the enveloping 

 venter of the ovary (c^) : its proximal part remains as a sort 

 of sheath round the base of the stalk, while its distal portion, 

 with the shrivelled remains of the neck (;/), is carried up by 

 the elongation of the .sporogonium and forms an extinguisher- 

 like cap or calyptra (c*, c) over the urn. 



As development goes on, the distal end of the urn be- 

 comes separated in the form of a lid (c*, c^, /), and certain 

 of the cells in its interior, called spore-mother cells, divide 

 each into four daughter cells, which acquire a double cell- 

 wall and constitute the spores (c^, sp) of the moss. 



When the spores are ripe the calyptra falls off or is blown 

 away by the wind, the lid separates from the urn, and the 

 spores are scattered. 



In germination, the protoplasm of the spore covered by 



