THK YOUNG SPOROPHYTE 67 



THE YOUNG SPOROPHYTE oi HELMINTHOSTACHYS. 



The only account that has yet been published of the young sporophyte of 

 Helminthostachys is that of Lang (Lang I), who examined at some length the 

 vascular system in the young sporophyte. Lang states that the young sporophyte 

 of Helminthostachys develops its first leaf as a large ternate foliage leaf, and when I 

 first examined the young plants which were collected in Ceylon 1 reached the same 

 conclusion; but on making sections of the young sporophyte it was found that in 

 all of the young plants that were sectioned the supposed cotyledon was really the 

 second leaf, the cotyledon itself being rudimentary and forming an inconspicuous 

 papilla at the base of the second leaf, which was the first to develop a functional 

 lamina. Further examination of a number of other specimens showed that this 

 rudimentary cotyledon was also present and it is probable that the cotyledon in 

 Helminthostachys, as in Botrychium lunaria and Ophioglossum vulgatum, is always 

 a rudimentary organ which never appears above the ground. 



The youngest sporophytes oi Helminthostachys which were found already had 

 the second leaf well developed and the first root had emerged. The ternate second 

 leaf (fig. 10, C) shows clearly that the ternate form is the result of an unequal dichot- 

 omy, such as is common in the early leaves of many ferns. The second leaf of 

 Helminthostachys closely resembles the cotyledon oi Botrychium virginianum and, 

 like that, usually possesses two vascular bundles extending through the long, slender 

 petiole. At the base of the leaf there is a conspicuous stipular sheath which 

 completely incloses the next younger leaf, as it does in Botrychium lunaria. The two 

 bundles of the petiole contribute to the two lateral lobes of the leaf as they do in the 

 cotyledon of Botrychium virgiiuanum, and one of these, forking again, gives rise 

 to the terminal lobe and smaller lateral lobe. The venation of the second leaf, 

 especially in its younger stages, is almost perfectly dichotomous and is more like 

 the venation in the leaves oi Botrychium lunaria than that of B. virginiaiium. With 

 the enlargement of the leaf segments the venation more nearly approaches the 

 pinnate arrangement found in the later leaves. 



While the young sporophyte in Helminthostachys in its earliest stages shows a 

 general resemblance to that of Botrychium virginianum, a difference is very soon 

 noted. The young plant, very soon after the formation of the cotyledon, develops 

 a conspicuous internode between the cotyledon and the root, and the stem rapidly 

 elongates as the sporophyte grows, so that it soon shows the characteristic elongated 

 rhizome of the older sporophyte. 



Unfortunately I was unable to secure any very young sporophytes, my youngest 

 specimens already having the second leaf nearly fully developed. According to 

 Lang, the arrangement of the primary organs of the young sporophyte is the same 

 as in B. virginianum, but I could make no study of the origin of the vascular system 

 in the sporophyte before the first leaf and root had emerged from the prothallium. 



To judge from longitudinal sections of the youngest plants obtained, the 

 relation of the first leaf and root is the same as in Botrychium virginianum and the 

 base of the young sporophyte closely resembles that of the latter. As in Botrychium, 

 the foot is very large and conspicuous, forming a large, hemispherical body sur- 

 rounded by the prothallial tissue. The large primary root grows out at right angles 

 to the foot and is continued into the axis of the sporophyte, which grows up verti- 

 cally. None of the specimens were young enough to show the relation of the stem 

 apex to the first leaf and root, as in the youngest specimens the axis had already- 

 begun to elongate and an evident internode was formed between the base of the 

 first leaf and the root. 



