The Origin of the Roots in Lycopodium Selago. 
BY 
E. MARY SAXELBY, B.Sc. 
Graduate Scholar in the University of Manchester. 
With Plate III. 
T HE question of the origin of the roots of Lycopodiaceae has received 
the most detailed discussion from Bruchmann 1 ’ 2 and from Van 
Tieghem, 3 both of whom worked especially at Lycopodium inundatum* 
They arrived at different conclusions, and it was suggested to me that an 
examination of the root origin in some other species of Lycopodium might 
throw some light on the subject. My observations of L. Selago , however, 
incline me to think that the process in this species differs from that 
described by either Bruchmann or Van Tieghem, although Van Tieghem 4 
states that L. Selago agrees with L. inundatum in all but the course 
followed by the root through the cortex. 
I have chosen for investigation Z. Selago , since this species differs 
considerably in habit from L. inundatum , and does not appear to have 
been so carefully studied in this connexion as has the latter species. 
L. Selago is of particular interest, since it is an upright form of Lycopodium , 
and the roots arising near the apex pass down through the cortex of 
the stem, each root surrounded by its own cortical tissue (see PI. Ill, Fig. 7). 
In both papers by Bruchmann it is stated that in L. inundatum the 
root arises from several layers of the inner cortex, the plerome periblem 
and dermatogen of the root all being formed from the cortex of the stem 
The pericycle, which he prefers to call pericambium, at a later stage 
helps to connect the base of the root on to the stem. He calls the layer 
of cells adjacent to the primary tracheids of the stem the pericambium, 
and he considers that this layer is formed from the periblem of the stem. 
1 Bruchmann ( a ), Uber Anlage und Wachstum der Wurzeln von Lycopodium und Isoetes . Jen. 
Zeit. fiir Med. u. Nat., Bd. viii, 1874. 
3 Bruchmann ( b ), Uber Prothallien u. Keimpflanzen mehrer europaischer Lycopodien, 1898. 
3 Van Tieghem et Douliot, L’origine des membres endogenes dans les plantes vasculaires. 
Ann. des Sc. Nat., 7 e serie, tome viii, 1888. 
4 Van Tieghem, loc. cit., p. 557. 
[Annals of Botany, Vol. XXII. No. LXXXV. January, 1908.] 
