1902.] NATURAL SCIENCES OF PHILADELPHIA. 125 



coat, with the lifting off of flaky pieces (figs. 4 and 5). The 

 tegmen is also broken through by the knob-like protruding por- 

 tion of the embryo (figs. 4, 5). The radicle first protrudes as a 

 roughened thick tubercular mass about one-fourth of an inch long, 

 and from this arise six to ten secondary roots (fig. 4). The 

 plumule, which points away from the tip of the radicle, lies in a 

 cup-shaped depression formed by the swollen petiole-like bases of 

 the conferruminate cotyledons (figs. 7, 8a). It is about two-fifths 

 of an inch long. The base of it appears as a small knob through 

 the slit left between the bases of the cotyledons. The hypocotyl is 

 about one-fourth of an inch long. As the radicle grows out and 

 down, the plumule straightens out by first assuming a U-shaped 

 form (figs. 8, 8a). Later it becomes straight and grows upright. 

 The radicle of Carapa guianensis does not assume the rounded, tuber- 

 like form of that of the mangrove plant (Xylocarpus granatum 

 Koen., Carapa mo luccensis Lam.), figured and described by Kars- 

 ten, nor does it show the horizontal aerating roots which develop 

 vertically horn-like upgrowths with numerous lenticels for breathing 

 purposes. The germination of the seeds of these two species is 

 somewhat similar. The greatest difference lies in the formation of 

 tuber-like radicle and the pneumatodes in Carapa mo luccensis, the 

 latter being developed as an adaptation to the conditions of a 

 littoral life and growth in the water. Carapa guianensis, a land 

 plant, in not possessing these structures during germination, shows 

 that it is more primitive than the tree of mangrove habit which 

 lives with its roots submerged. 



The stem of the seedling rapidly elongates, bearing at first closely 

 appressed scale leaves (fig. 10). After a time, there arises a pair 

 of opposite, abruptly pinnate, bijugate leaves; the stem becoming 

 woody at the base. Then succeed a pair of sub-opposite leaves 

 which are large and monojugate. Each leaflet has a swollen pul- 

 vinus-like base. The succeeding leaves are bijugate ; each leaflet 

 has a pulvinus and thick dark-green blade about three inches wide 

 and five inches long:. 



