12 
Birbal Sahni. 
Such primary dormant buds are commonly seen on Fern stems < 
and as we have seen, very frequently in the proximity of leaf-bases. 
In accordance with the insignificant demands that they make on 
the food resources of the plant so long as they are in a dormant 
condition, a single thread-like strand is seen to connect them to the 
main vascular system, although the latter may be solenostelic or 
even dictyostelic. But when a plant has reached a certain develop¬ 
ment the surplus energy is diverted into these side channels. In 
response to the increased flow of food and water the thin strand at 
the base of the young branch is succeeded distally by a stouter and 
more efficient conducting system. If the adult stem has a protostele 
in the main axis, the branch usually retains a protostele ; if the main 
axis is soleno- or dictyostelic the vascular system of the branch 
expands accordingly. A branch of a dictyostelic Fern, for example, 
produced in these conditions, would correspond to what we find in 
Alsophila excelsa, Aspidium cristatum } A. spinulosum (Fig. 1, F). 
At this point the question may reasonably be asked, why is it 
that in the case of a soleno- or dictyostelic Fern the dorma'nt bud 
does not always establish a diminutive soleno- or dictyostelic 
connexion with the main axis, rather than a protostelic one ? We 
must remember that we have hitherto dealt only with buds which 
became dormant almost immediately after their origin. This is not 
always the case, however. The dormant stage may be delayed for 
a longer or shorter period after the division of the main growing 
point, 1 so that for a time the products of division have a more or less 
equal share of the food resources, and naturally develop a similar 
vascular system. This is, in fact, what happens in Polypodimn 
vulgare according to Klein’s observations, 2 and Stenzel’s figures of 
the same species ( loc. cit., 1861, pi. V) show the reticulate stele of 
the main axis giving off similar steles to the branches. Klein’s 
observations on P. Heracleiun and P. quercifolium 3 are further 
examples of the same phenomenon. 
Wiss. V, 1857, Math.-Phi’s., Klasse 111, p. 651) that the stolons of Nephrolepis 
arise from adventitious buds was shown to be incorrect by Sperlich in 1906 
(Flora, p. 469). Further, Sadebeck’s statement (in Engler u. Prantl, Nat. 
Pflanzenfam. I, 4, 1st part, p. 44) that the branching of Ferns with dorsiventral 
rhizomes is due to lateral buds traceable to the main apex, is in support of the 
general view expressed in 1861 by Stenzel (loc. cit., p. 34) that the branching of 
the Fern stem has no relation to adventitious buds. Pringsheim appears to 
have been the first to express this opinion (Bot. Ztg., 1853, p. 609), which was 
in 1855 adopted by Irmisch (see Hofmeister in Pringsheim’s Jahrb., Vol. Ill 
1863, p. 279). If this is true, as seems probable, there is no doubt also that 
the buds in Cheiropleuria, Lopliosovia and other Ferns investigated by Professor 
Bower, are of primary origin. 
1 Schoute, Ann. Buit., 1906, p. 88. 
1 Klein, L., Bot. Ztg., 1884, p. 585. 
* Klein, Nova Acta, 1881, Bd. XLI1, pp. 353, 366. 
