Fructification. 



35 



Fig. 13. Tnckomanes radicans, 

 Swz. ■ Enlarged section showing 

 metliod of fnictification. (Original.) 



57. Dicksonia. — In this genus the small globular sorus is borne 

 in an elevated, globular receptacle and enclosed in an inferior, 

 membranous, cup-shaped indusium. The veins are always free. 



58. Trichomanes (Fig. 13) has 

 sessile sporangia borne on a filiform 

 receptacle at the summit of a vein. 

 The indusia are tubular or funnel- 

 shaped with an expanded and often 

 sofnewhat two-lipped mouth. 



59. Lygodiura. — In our species of 

 climbing-fern the fructification is 

 borne on contracted, forked pinnules 

 occupying the upper portion of the 

 frond. The ovoid sporangia are solitary or occa- 

 sionally in pairs and are borne in the axils of the 

 large, imbricated, scale-like indusia which are fixed 

 by their bases to short, oblique veinlets. 



60. Aneimia. — In this genus the two lowest 

 branches of the frond bear panicles of fruit at the 

 end of very long stalks. The ovate sporangia 

 are sessile in two rows along the branchlets of 

 the panicle without special covering of any kind. 

 In the section represented by our species' the 

 veins are free. 



61. Schizsea. — In this genus the large ovoid 

 Sporangia are sessile in double rows along the 

 single vein of the narrow fertile divisions. In our 

 species the pairs of fertile pinnae form a distichous 

 spike. (Fig. 14). 



62. Osmunda has the large globose sporangia, 

 short-stalked and borne on the contracted fertile 

 portions of the frond. In the cinnamon-fern {O. 

 cinnamo-mea) the fertile fronds are entirely dis- 

 tinct from the sterile, yet manifesting a tendency 

 to variation in the var.frondosa. In the interrupted 

 flowering-fern (O. Claytoniana), the fructification 

 is confined to a few of the middle pinnae of the 

 frond. In the royal flowering-fern (<9. regalis) the 

 fructification is borne at the apex of the fronds. 



63. Ophioglossum.— In the adder-tongues the '^'S-i*. ScUzxa 

 . , , , . f , pusiUa, Pursh. En- 



sporangia are large and cohere in two ranks along a^^ ^i^^^ ^^^^..^i 



the margins of a single spike, opening by a trans- size. (Original.) 



