1 77 
the Prothallus of Equisehtm debile , Roxb. 
a gap appears in the latter (Fig. 41) and parenchyma passes into the middle 
of the stele. The two protoxylem groups bend towards each other and 
later turn completely inwards. The course of the third protoxylem group 
Text-fig. 40. 
Text-fig. 42. 
Text-fig. 41. Text-fig. 43. 
is not clear. A little higher the stele assumes the form of a hollow cylinder 
(Fig. 42), and still higher the bundles of the stem become separate from 
each other (Fig. 43). These changes are similar to those described by 
Jeffrey (as reported by Campbell) for Equisetum hiemale . 
N 
