The Structure and Development of the Prothallus of 
Equisetum debile, Roxb. 
BY 
SHIV RAM KASHYAP, B.A. (Cantab.), M.Sc. (Punjab), 
Professor of Botany , Government College , Lahore. 
With forty -five Figures in the Text. 
Introduction. 
A LL the species of Equisetum whose prothalli had been investigated 
- before 1905 are confined to Europe (Goebel, p. 195). The writer is 
not aware if any extra-European species have been investigated since then. 
As the prothalli of Equisetum debile whose range is given by Baker (‘Fern 
Allies ’, p. 5) as ‘ Tropical Asia from the Himalayas and Ceylon eastward 
through the Malay Isles to Fiji’, were found growing in large, numbers 
along the banks of the river Ravi in Lahore, and as they differed in general 
characters from the prothalli hitherto described, it was thought that a study 
of the development might bring out some interesting points. The result of 
this study carried on in the winter of 1912-13 is given in the following pages. 
Aitchison and Stewart describe Equisetum debile as the only species of 
Eqtiisetum occurring in the Punjab, and certainly this is the only species 
met with in or near Lahore. It may be mentioned that Baker remarks that 
this species is doubtfully distinct from Equisetum rcimosissiwmm , Desf., which 
is cosmopolitan in the warm temperate and tropical zones, but nothing is 
known as regards the prothallus of this latter species. 
Material. 
The plant grows in and near Lahore in great abundance along the 
banks of the river in sandy soil or in the shady and swampy soil of the 
wood along the river. In the former place it remains tufted and small, 
being only a foot or two high, but in the wood it may reach a height of 10 
to 15 feet, being supported by the neighbouring trees, and attain a thickness 
of half a centimetre. For general characters Baker’s ‘ Fern Allies ’ may be 
consulted. The small spikes are formed at the ends of ordinary branches 
[Annals of Botany, Vol. XXVIII. No. CIX. January, 1914.] 
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