THE EMBRYO 



139 



Angiopteris, but thev seem to take it for granted that a vascular strand is also 

 developed in the stem; at any rate they make no reference to the absence of such 

 a vascular strand from the stem region. In my earlier study of Marattta, I supposed 

 that a strand was developed which belonged to the stem itself, but a further exam- 

 ination of many plants, after a study of this point in the other genera, has made it 

 pretty clear that this supposed stem bundle really belongs to the second leaf, the 

 rudiment of which appears at a very early period. 



THE EMBRYO OF ANGIOPTERIS. 



In Angiopteris the embryo very early becomes more greatly elongated trans- 

 versely than is the case in Marattia, so that in a longitudinal section it appears as a 

 very much depressed oval (fig. 109); the epibasal region is larger than the hypobasal 



Fig. 109. 



A. Two sections of a young embryo of Angiopteris. The cells were badly shrunken. 



B. Diagrams showing arrangement of cells of same embryo. 



C. An older embryo, b b, basal wall; sr, stem apex; cot, cotyledon; f, foot. 



and the quadrant divisions are often still evident. Whether octant divisions are 

 formed in all the quadrants could not positively be determined, but Jonkmann 

 states that such is the case. There can usually be found in the young embryo a 

 nearly centrally placed large cell (tig. log, C, si), which probably is the initial cell of 

 the young stem. The position of this cell is not unlike that which occurs in the 



Fig. 1 10. 



Two longitudinal sections of an older embryo of Angiopteris. X200. The young root, r, is shown 

 in /?. st, stem apex; cot, cotyledon; /, foot. 



embryo of Equisetum, and at this stage there is also a certain resemblance to the em- 

 bryo of Botrycht um virginianum. As the embryo grows it tends to assume a more 

 nearly globular form (fig. no). The basal wall can still be imperfectly followed, the 

 hypobasal portion of the embryo being made up of the large cells forming the foot, 

 while above the basal wall the cell divisions are more active and the rudiments of 



