248 adj 
1892.) Noteworthy Anatomical and Physiological Researches. 119 
Il. With parenchyma differentiated into a central cylinder 
and parenchyma containing chlorophyll. 1. Central cylinder 
uniform; 3dtype, Mnium. 2 Central cylinder differentiated 
intoa medullary region and a surrounding pericyclic zone; 4th 
type, Polytrichum. 
In using the term ‘‘pericyclic zone,” the author remarks 
that ‘‘as to its development, it is not comparable to the 
pericycle of the phanerogams, and in general, a strict analogy 
cannot be established between the tissues of the stem of the 
mosses, a product of the asexual spore, and the stem of the 
higher plants, a product of the egg.” 
From this pericycle and central pith arise the leaf traces, 
which diverge from the center according to a law constant 
for each species. The trace reaches its maximum differen- 
tiation at the periphery of the stem as it passes into the leaf 
Costa. 
In mosses with a central cylinder, branch traces are found 
arising by differentiation of the medullary tissue and the 
Pericyclic zone. Here, also, the traces follow a law of diver- 
gence constant for each species. 
_ For his study of the leaf the author uses Polytrichum 
Juniperinum. He regards the chlorophyllose lamella as an 
angle, adjacent to the epidermis, is a hypoderm bundle, 
. e inside by the hypoderm sector. This struc- 
being more extensive at the periphery than the bundle, 
“cae to the epidermis laterally for some distance, and 
Hides rapidly toward the center forming a rude ¥ which 
with a an hypoderm bundle between its forks. In contact 
Peric lic inner end of the stem of this Y is the crescentic 
fee '€ sector, placed with its concavity outward and trans- 
oiivey the stem of the Y. Bounding this sector, along its 
along as. surface, is the central pith. Filling the spaces 
cortical € sides of the (tri)angular section are the three isolated 
pith. regions extending from the epidermis to the central 
ture, 
