Notes on Equisetum debile, Roxb 
BY 
SHIV RAM KASHYAP. 
With three Figures in the Text. 
i. The Endodermis. 
I T has long been known that the form and position of the endodermis 
of the stem in the genus Equisetum is very variable. Three different 
types may be distinguished : (i) one endodermal ring round each vascular 
bundle, (ii) two layers of endodermis, one outside and the other inside the 
ring of vascular bundles as a whole, (iii) one endodermal layer round the 
ring of vascular bundles as a whole. These different types are not restricted 
to different species of the genus exclusively, but two may occur in different 
parts of the same plant. The following, for example, is the condition of the 
endodermis according to Sadebeck (vide ‘ Nat. Pflanzenfamilien ’). In the 
internodes of the aerial shoots of E. Heleocharis the endodermis is of the 
first type; in E. hiemale , E. ramosissimum , E. trachyodon , and E. variegatum 
it is of the second type; and in E.palustre and E. scirpoides it is of the 
third type. In the internodes of the underground portion of the shoots of 
E. hiemale , E. ramosissimum , and E. trachyodon , however, the endodermis is 
of the first type, though in the aerial portion it is of the second type. In 
the internodes of the underground portion of the shoots of E. sylvaticum 
the endodermis is of the second type, though in the aerial portion it is of the 
third type. In most investigated species, however, according to Sadebeck, 
this difference in the aerial and underground portions of the shoot is not 
present, e. g. in E. arvense , E. maximum , E. palustre , E. scirpoides, 
E. Heleocharis , and E. variegatum ; but in the underground tuberous 
swellings of E. palustre , E. arvense , and E. sylvaticum Pfitzer found an 
endodermis of the first type . 1 
If we do not take into consideration the exceptional case of the under- 
ground tuberous swellings of the three species mentioned above on account 
of their great modification, it is clear from the above description that in 
those species where two different forms of the endodermis occur in different 
parts of the stem, an endodermis of the first type is associated with the 
1 For further details see Englerand Prantl: Nat. Pflanzenfamilien. 
[Annals of Botany, Vol. XXXI. Nos. CXXIII and CXXIV. July and October, 1917.] 
