68 



III! OPHIOGLOSSALES 



The longitudinal section of the young sporophyte at tin's time shews that the 

 thick stele of the root bends upward and is continued into the axis, which already 

 is a good deal elongated ami has carried up the young leaves, which an- separated 

 from each other by conspicuous internodes. I In young sporophyte at this sta<M 

 thus differs strikingly from the corresponding stages in Ophioglossum ami Botrych- 

 ium, with tluir very closely crowded leaves with no appreciable internodes between 

 them ( fig. 4''). 



A single stele extends through the- axis from its junction with the mot stele ami 

 forks below the insertion ot the rudimentary first hat, one branch passing into tin 

 cotyledon, the other continuing upward ami forming the trace tor the second leal, 

 at whose base is seated the apical hud. 



Whether in the younger stages, before the development of the second leaf, the 

 vasculai system ot the young sporophyte would show the same relations of the steles 

 ol the loot and cotyledon, as in Botrychium, remains to he seen; hut from the general 

 similarity in the structure ot the young sporophytes ot" the two this is quite likely: 



yet it is possible that the stem apex is 

 more prominent in the early stages ot 

 Helminthostachys and part ot the stele 

 which is found in the elongated stem 

 maj he of cauline origin, although this 

 is hardly indicated by the condition ot 

 things in the apical meristem ot the 

 youngest sporophytes that were ex- 

 amined. 



I he toot is composed of large- 

 celled, thin-walled parenchyma, with 

 no noticeable differences between the 

 inner tissue and that of the periphery. 

 The stele of the loot is continued up- 

 ward without interruption into that ot 

 the shoot (fig. 46, fi). Probably at an 

 earlier period there would have been, 

 as in Botrychium, simply the continu- 

 ous stile ot the root and cotyledon. 

 At the junction of the root stele with 

 that of the axis there is a marked en- 

 largement, and the short, somewhal ir- 

 regular tracheidsare decidedly broader 

 than those eithei in the root or in tin- portion ot the stile above the junction. I he 

 tracheids toward the- outside of the central region an- slender and have delicate 

 reticulations, which closely approximate the form of true spiral thickenings. I hese 

 are the protoxylem elements and can he traced upward and downward into tin 

 stem and loot, respectively. I he secondary tracheary tissue is marked by broad, 

 reticulate thickenings, and these in the largest tracheids an- replaced In conspicu- 

 ous oval 01 nearly round bordered pits, vt i\ much like those which are found in Bo- 

 trychium I tig. 46, / I. 



\ho\e rhi' base of the root there is a long mteinode below the cotyledon, and 

 through this runs the single axial stele. ( m the same side ot the axis as flu- primary 

 root may be seen the cotyledon, which closely resembles in form the young cotyledon 

 of Botrychium virginianum, hut instead of developing into a functional leaf it is 

 arrested in its growth before the lamina is fully developed. As in the cotyledon of 



Fig. 45. 



\. Young sporophyte "f Helminthostachys, attached to gameto- 

 tyledon; r^r, first and & ts. X 2. 



it. Leal From an ol ler 1 01 Dphytc. ■ 1 . 



