594 F. 0, BOWER. 
different type of development, which, moreover, he seems to find 
constant. In this case the following succession of members is 
found by him—(1) two cotyledons, (2) two small plumular leaves 
decussating with the above, (3) a stem about two lines long, 
bearing (a) an almost imperceptible Jracteole, (4) a true leaf, 
(c) two further leaves, “alternate but very close together, so that 
they appear opposite, and which seem to terminate the tigellum.” 
I do not doubt that this description points to a further deve- 
lopment of the plumule than any which has occurred in the 
plants at Kew. In these the axis remained in all cases very 
short, and certainly did not attain a length at all approaching 
two lines, which is the length stated by M. Naudin for his 
lant. 
I conclude, then, that the observations of M. Naudin do not 
affect the above interpretation of my observations on the plants 
at Kew, but rather point to the conclusion that the type of 
development which I have described is not universal. 
Further, I think it is unlikely that the Kew plants will enter on 
the further stage of plumular development as deseribed by 
M. Naudin. The oldest seedlings now living at Kew were sown 
in August, 1880 (i.e. five or six months before those of M. 
Naudin). These, when last I saw them (July, 1881), showed 
no outward signs of any deviation from the type which I have 
described as normal. Their two plumular leaves were of healthy 
appearance, and had attained a size almost equal to that of the 
cotyledons. This condition may be contrasted with that de- 
scribed by M. Naudin. He expressly mentions that the pair 
of leaves succeeding the cotyledons are “ very smad/,” and speaks 
of their “‘ growth being apparently arrested.” May we not have to 
deal with two alternative types of development—(1) one in which 
the first pair of plumular leaves are large, while further develop- 
ment of the main axis is arrested; (2) one where the first pair of 
plumular leaves are small, while the main axis grows in length 
and forms further appendicular members ? 
Lastly, M. Naudin suggests the possibility of the two members, 
which have been hitherto regarded as leaves, being really flattened 
branches. In connection with this I can only say that if (as the 
specimens I have examined lead me to believe is the case) the 
two leaf-like members of the mature plant are xormally derived 
from the first pair of plumular structures, as described in my 
first paper, there can be little doubt of their foliar nature. The 
only alternative would be the assumption that they are extra- 
axillary, z.e. adventitious axes, developed nearer to the apex 
than the youngest leaves, a supposition which is warranted 
neither by their structure, appearance, or origin. 
August 29th, 1881. 
