Common Club-Moss — continued. 



Fig. 8. Microspore rendered transparent to show internal division. 



The contents break up into cells, one of which does not form Antherozoids, and may therefore be regarded as 

 a rudimentary Male Prothallus. 



Fig. 9. Macrospore six weeks after escaping from sporangium, and before rupture of the exospore. 

 Prothallus rudimentary, within the spore, bearing Archegonia. 



Endosperm, loose cellular tissue formed by free cell-formation, i.e. a grouping of masses of protoplasm around 

 small internal centres, and forming cell-walls about them, independent of prothallus, but supplying nourishment to it. 



Figs. 10 and 11. Archegonium before and after fertilization. 



The neck of the Archegonium is at first closed, but afterwards opens to give access to the Antherozoids. 

 The central cell after fertilization divides first into two — one half further dividing and giving rise to stem and 

 leaves, the other half also dividing and forming Suspensor. 



Fig. 12. Embryo still within the spore. 



The Suspensor is a temporary structure, and there are no indications of the root so long as it lasts, but when 

 it withers away the end of the embryo in connection with it forms the root 



The Foot is always embedded in the Endosperm, serving as a means of connection between the embryo and its 

 early food-supplies. 



Life History Diagram. — The upright fertile shoot bears the sporangia in the axils of its leaves — either Micro- or Macro- sporangia. 

 The Microspore divides internally into antheridial cells, all but one barren basal cell, which represents a Male Prothallus. 

 The Macrospore forms an internal Prothallus bearing Archegonia, and the rest of the spore is filled with Endosperm for food- 

 supplies. The Archegonia are exposed by the rupturing of the wall of the spore, and the Antherozoids liberated from the 

 Microspore fertilize the central cell. The Embryo thus formed is at first provided with a Suspensor, and grows right down 

 into the Endosperm living at its expense ; but by and by the Suspensor withers, the root appears, the growing point begins to 

 turn round, and the line of growth becomes horizontal, as in Fig. 12. Finally, the stem and root structures assume their 

 upright and downright positions, and the young plant emerges from the spore near the point where its development began. 



CLASSIFICATION OF SELAGINELLA. 



Sub-kingdom. — Vascular Cryptogams. 

 Class. — Dichotomae. 

 Order. — Ligulatae. 



Leaves ligulate. 



Spores of two kinds — Microspores and Macrospores. 

 Family. — Selaginelleae. 



Stem long and leaves short. 



Prothallus small, male and female, confined to the spore. 

 Genus. — Selaginella — the only genus. 



Advance in Organization. — There are two distinct kinds of Sporangia — the Microsporangia, producing Microspores and the Macro- 

 sporangia, producing Macrospores. 



The Microspore produces the smallest possible Male Prothallus in the interior of the spore, and not outside, as usual. 

 The Macrospore also developes an internal Female Prothallus, only protruding slightly when the exospore ruptures. 

 Endosperm is present, as in the seed of higher plants. 

 Embryo provided with Suspensor and two Cotyledons, as in higher plants. 



