204 Lang . — Studies in the Morphology and 
attention has been paid to such larger species as B. ternatum and 
B. virginianum. Russow 1 studied B. rutaefolium (A. B. and Koch.), a form 
of B. ternatum , while the structure of B. virginianum is well known 
from the work of Jeffrey 2 and Campbell . 3 A knowledge of these species 
of the section Phyllotrichium does not, however, explain the structure 
of B. (E ubotrychium) Lunaria ; this appears to be of special importance for 
the interpretation of the stelar anatomy in the genus. 
The starting-point of my re-examination of B. Lunaria was the need 
of fuller information regarding the internal endodermis of this plant for 
comparison with Helminthostachys . The internal endodermis was described 
for young plants of B. Lunaria by Poirault 4 and Van Tieghem , 5 and while 
my work has been in hand Bower 6 has given a more detailed description 
than we previously possessed of this feature in the anatomy. Part of the 
present paper traverses some of the ground covered by Bower. The study 
of the progression in structure from the embryonic to the adult regions of 
the rhizome has led to the recognition of some new points in the structure 
of the stele and leaf-trace and to the investigation of the branching of the 
rhizome. 
The description given by Hofmeister , 7 supplemented by the investiga- 
tions of Bruchmann , 8 shows that the young sporophyte is attached to the 
subterranean prothallus by a fairly large foot. The first leaves have the 
form of small scales, and the first roots, corresponding to these, develop on 
a region of the stem, which remains very short. According to Bruchmann, 
elongation of the axis does not become marked until five or six roots have 
developed, and it is not until the eighth or tenth leaf that the plant appears 
above the surface of the soil. The detailed study of the anatomy and 
growth relations of very young sporophytes of successive ages would be 
of great interest, but lack of sufficient suitable material prevented me from 
attacking the problem in this way. Uninjured plants, however, even when 
of large size, retain at the base the first-formed region of the rhizome. The 
structure of this region can thus be easily studied and the transition to the 
adult structure followed. 
When a number of plants are compared they are found to present 
considerable variety in external form. A number of roots are always 
attached close together at the lower end of the rhizome, and this basal 
region evidently bears the crowded roots that are such a conspicuous feature 
of the young sporophytes figured by Hofmeister and Bruchmann. Some- 
times the transition to the thicker region of the rhizome with adult structure 
is a direct one ; the diameter of the rhizome increases until the full size 
1 Vergleichende Untersuchungen, p. 119. 2 Trans. Canad. Inst., vol. v, p. 265. 
3 Most recently in The Eusporangiatae, to which work reference may also be made for the 
general bibliography of the subject. 4 Ann. Sci. Nat., Ser. 7, t. 18, 1893, pp. 169, 170. 
6 Journ. de Botanique, 1890, p. 405. G Annals of Botany, 1911, p. 537 . 
7 Higher Cryptogamia. Ray Soc., 1862, p. 307. 8 Flora, 1906, p. 203. 
