Seedling Structure of Gy mno sperms. I. 699 
Before passing on, attention may be drawn to another feature of 
resemblance to Cephalotaxus and Tax us which is found in the presence 
of a well-marked assise de soutien in the roots of Juniperus. This is 
especially well marked in J. bermudiana , where the thickenings extend 
from the layer of cortical cells immediately bounding the endodermis, 
outwards towards the periphery. 
The thickenings of the walls of the outer cells are much smaller than 
those of the elements nearer the endodermis. 
Cupressus obtusa , C. Koch. All the seedlings examined had two 
cotyledons, which, as regards their form and structure, closely resemble 
Juniperus . The only features of difference are that, in the plant under 
consideration, transfusion elements are less numerous and the vascular 
strand has but one or two centripetal tracheae ; the bundle is, therefore, 
but very slightly mesarch. 
Transition. The changes which lead to root-structure need no 
description, inasmuch as they are similar to those exhibited by Juniperus 
virginianum . It is only necessary to remark that the attainment of the 
exarch position by the protoxylem of the cotyledon-traces is rather more 
obscure than in any species of Juniperus examined ; indeed, it is practically 
impossible to trace the movement of the protoxylem elements, owing to 
the compact nature of the xylem-masses. The apparent outward passage 
of these tracheae is considerably aided by the disappearance of some of 
the metaxylem, and by the inward movement of the rest of these elements. 
The transition is fairly rapid "when once the central cylinder has been 
reached, so that a root-structure obtains in the higher regions of the 
hypocotyledonary axis. 
Cupressus Lawsoniana, A. Murray. The number of cotyledons and 
their structure is the same as in C. obtusa. The only feature of difference 
is that in C. Lawsoniana the bundles are somewhat larger and, towards the 
base of the seed-leaves, are more tangentially expanded. 
Transition. The transition-phenomena more closely resemble those 
of Juniperus virginiana than do those of C. obLisa , for the rearrangement 
of the wood, culminating in the exarch position of the protoxylem, is more 
definite. This redistribution usually takes place after the central region 
of the axis has been reached, but in one instance it was found that the 
bundle of one of the cotyledons underwent bifurcation of the phloem 
and partial rotation of the xylem during the inward passage from the 
seed-leaf. There is thus a similar variation in this plant to that already 
described for species of Juniperus. 
Cupressus pisifera , C. Koch., in all respects resembles C. Law- 
soniana. ' ' ^ ' ; *■ 
Cupressus torulosa , D. Don. The number of cotyledons varies from 
three to five; thus out of twelve plants, nine had three, two had four, 
