Anatomy of the Ophioglossaceae . 
29 
cot 
primary or first root grows out and turns downwards into the soil, while 
the hypocotyl lengthens, carrying up the cotyledon and the terminal bud. 
The relations of the basal part of the plant to the prothallus remain 
unchanged, though the suspensor may be more or less completely broken 
down. An example of this is afforded by Text-fig. 4, D, where the suspensor 
of the plant is unrecognizable, although the cavity which it occupied (j) is 
evident, leading down from the archegonial neck. PI. Ill, Photo. 12 shows 
a fairly well preserved suspensor in relation to the base of a young plant. 
The large upper cell of the suspensor was undivided, while the second tier 
of the suspensor was divided up into cells. The suspensor figured in PI. Ill, 
Photo. 13 is from another young plant. It is of interest in that it shows the 
remains of the archegonial neck above (ar) and also because in this case 
both tiers of the suspensor have become multicellular. 
The plant in Text-fig. 5 which was cut longitudinally 
shows the suspensor (s) in E and F. 
The reconstructed embryo (Text-fig. 3, C), the 
young plants described, and a number of others 
studied agree in the orientation of the organs of the 
embryo in relation to the suspensor and present the 
usual type of this. It is shown also in Text-fig. 8, 
which represents a small plant dissected free from 
the prothallus. The position of the suspensor was 
recognizable at s t the foot (/) bulged out to one side, 
while the primary root (r) had grown out on the 
opposite side. The plant differed from the mature 
embryo in the marked elongation of the hypocotyl 
(hyp)) but the first leaf (cot) is seen to stand above 
the first root, while the enlarged apical bud is en- 
closed by the sheath of the first leaf. Below the bud 
the second root (r 2 ) is seen. 
The general appearance and external morphology of the young plants 
have already been described and figured in my earlier paper and also by 
Campbell. In all the young plants observed by Campbell the first leaf or 
cotyledon remained rudimentary, and did not come above ground or expand 
its lamina. I have also met with examples of this behaviour, but in the 
majority of the young plants I have studied I find that, as described in my 
earlier paper, the first leaf became fully developed and expanded above 
ground. I am thus unable to accept Campbell’s generalization 1 that ‘ it is 
probable that the cotyledon in Helminthostachys , as in Botrychium lunar ia 
and Ophioglossum vulgatum , is always a rudimentary organ and never appears 
above ground \ The fact is that it may be either fully developed or more 
or less arrested, and presumably the former condition is the more primitive. 
1 loc. cit., p. 67. 
Text-fig. 8. Basal re- 
gion of a young plant de- 
tached from the prothallus 
and viewed from the suspen- 
sor side, s, suspensor ; f, 
foot ; r, primary root ; hyp , 
hypocotyl ; cot , first leaf ; 
bud, apical bud ; r 2 , second 
root. 
