PTERIDOPHYTES 



153 



FIG. 359. Lpo- 



medium that grows among the blocks of sporogenous cells and ramifies 

 ?nto every intercellular space (fig. 360). 



Gametophyte. The gametophyte is of the Lyco podium type. In 

 Ophioglossum, which is regarded as the most primitive genus the game- 

 tophyte is a" tuberous, subterranean body that gives 

 rise to aerial green lobes that bear the sex organs. 

 In Botrychium there is no aerial portion, the game- 

 tophyte being completely subterranean and tuberous 

 (fig. 361). In Helminthostachys the gametophyte is 

 somewhat intermediate in structure, the tuberous body 

 giving rise to a cylindrical aerial process that bears 

 the sex organs. In every case the tuberous body ra.ngia.ci'6phiogios- 

 contains an endophytic fungus, as in the gametophyte su : diagrammatic 

 of Lycopodium. It is evident that the gametophyte ^Jg 

 of the Ophioglossales suggests that of the Lyco- t he two' 



podiales; but that the nous bands at 

 sporophyte is more .ike j^JST ~ 

 that of Filicales. 



Sex organs. The antheridia develop 

 as usual among the eusporangiates, the 

 inner cell, following the periclinal division 

 of the superficial initial, giving rise to the 

 spermatogenous tissue. The sperms are 

 large, coiled, and multiciliate, a type not 

 found among the Lycopodiales, but char- 

 acteristic of the Filicales. 



The archegonium of Ophioglossum has 

 a very short neck, the neck canal, cells 

 being only two in number, the same 

 reduced number as in Equiselum. In 

 Botrychium (figs. 362-365) the neck of the 

 archegonium is long, but contains only 



mature * sporangium of Ophio- f ur neck canal cells. 



glossum, showing the tapetal Embryo. In general there is no sus- 



plasmodium (with nuclei) among pensor ; but in the rece ntly described genus 

 the groups of mother cells. r 



After BOWER. Sceptridium a massive suspensor is re- 



ported, at least for one species (formerly 



Botrychium obliquum). There is no differentiation of the great body 

 regions at the quadrant stage, but in Botrychium, for example, there is 



FIG. 360. Portion of a nearly 



