28o TRANSACTIONS OF THE CANADIAN INSTITUTE. [VOL. V. 



derived from the shoot-apex. Sadebeck"? makes the following state- 

 ment concerning the equisetaceous embryo : — " Nach meinen Unter- 

 suchungen bin ich vielmehr zu dem Resultat gekommen, dass die obere 

 Halfte des noch zweizelligen Embryo ganz unmittelbar die primare 

 Axe darstellt, aus welcher sich in gleicher Weise, vvie spater bei der 

 ervvachsenen Stammknospe die Blatter erzeugen." 



The embryo of Isoetes echinospora, as described by Campbell,^" also 

 resembles in a measure that of B. virginianuni. It has a large foot 

 originating from both the hypobasal quadrants, which by its position and 

 size, at least, somewhat strikingly resembles that oi Botrychium. In the 

 case of the latter, it is quite impossible to state from which of the primi- 

 tive divisions of the fertilized Q^^, the foot takes its origin. A resem- 

 blance also exists in the formation of the root and shoot from the upper 

 part of the embryo. In /. ediinospora, however, the cotyledon is the 

 first shoot-organ to appear, and the stem-meristem does not definitely 

 develop until later, although there is an indication of its existence from 

 the first. 



It is not to be supposed, however, that these resemblances are in any 

 way to be considered as indicative of relationship, for the development 

 of the embryo may vary greatly in the same natural group. In the 

 Mm'attiacece, for example, both Angiopteris and Marattia, as described 

 by Farmer^' and Campbell,^^ are distinguished by the precocious 

 development of the cotyledon. In Dancea, ^3 on the other hand, it is the 

 root which first shows considerable development. A somewhat similar 

 state of affairs has been observed by the writer in the Equisetacea. 

 Equisetuni arvense and E. hieinale have a precocious root, whilst E. 

 limosum and E. palustre develop first the shoot-organs. Among the 

 Opliioglossacece themselves, in OpJiioglossuvi pedunculosuvi, the cotyledon 

 is the first organ to rupture the calyptra. In Botrychiuni viigitiianum 

 and B. Lunaria, the root is prior in appearance. 



In figure 48, is represented an embryo, which, although larger, is yet 

 younger than that in figure 47. At a and b are probably the root and 

 shoot initials. Figure 49 is an older stage than figure 47. The root, r, is 

 already well advanced and its apical region is fully developed. Behind 



19. Die Entwick. d. Keimes d. Schachtelhalme. Pringsheim. Jahrbucher f. Wiss. Botanik. 

 Bd. xi., p. 582. 



20. Annals of Botany, vol. v., p. 244. 



21. Annals of Botany, %ol. vi., p. 265. 



22. Annals of Botany, vol. viii. 



25. Brebncr, G. On the Prothallus and Embryo of Danea simpUcifolia. Annals of Botany, vol. x., 

 p. 109. 



