712 
Thomas. — Seedling Anatomy of Ranales , &c. 
23 
petioles. Proceeding downwards, root structure which in Anona is diarch 
is attained at a higher level than in Calycanthus. 
A. reticulata presents similar features. 
Lauraceae. 
Laurus Sassafras. The top of the hypocotyl shows four groups of 
phloem and xylem in the diagonal planes, with two or three very small 
crushed and almost obliterated protoxylem elements isolated in the cotyle- 
donary plane. As these tissues are followed upwards they are seen to pass 
into the cotyledons, as in the previous families forming a double bundle 
which at the base of the petiole detaches two main laterals. In other words, 
the main lateral strands which in Magnolia tripetala , M. acuminata , and 
M. Soulangeana pass into the hypocotyledonary axis independently, 
sweeping round so as to enter the stele in the intercotyledonary plane, in 
L. Sassafras merge with the double bundle at the cotyledonary node and 
thus enter the stele as one unit. Downwards the hypocotyledonary 
arrangements merge into those of a tetrach root 
as the intercotyledonary protoxylem poles become 
defined. 
Laurus nobilis presents an octarch stage in the 
seedlings examined, which were, however, too old. 
Cassytha is described by Mirande as tetrarch. 
Laurus and the species Lycium and aristata 
of Berberis present the so-called * Anemarrhena * 
type reported by de Fraine as occurring in 
Cactaceae and by Lee in Compositae, in which it 
may be said that the xylem of the cotyledonary strand divides into three 
and the phloem into two to form a tetrarch root. 
I have been familiar with this type for many years and Althaea Rosea 
(PL LI, Figs. 23-6) presents a very good instance of it. In this case the 
lateral strands are only independent in the lamina and are merged with the 
central one throughout the petiole, which thus possesses an extended kidney- 
bean-shaped ‘ double ’ bundle, the central protoxylem of which is external at 
the cotyledonary node (PI. LI, Fig. 24). Althaea differs from Laurus 
Sassafras only with regard to the degree of independence of the laterals, or, 
in other words, with regard to the exact point of approximation with the 
double bundle in the cotyledon. 
The constancy of the Ranunculaceous type is in contrast to the variation 
met with in the few members examined of the other Ranalean families. 
They furnish, in addition to the ‘ Anemarrhena * type of Berberis and 
Laurus , the series in the Magnoliaceae (Text-fig. 25, 1, 3, and 4) in which 
Liriodendron links the tetrarch and diarch forms. Liriodendron and 
Decaisnea couple presence of laterals with a diarch root (Text-fig. 25, 3), while 
Text-figs. 23 
Laurus Sassafras 
bills . § nat. size. 
24. 23, 
24, L. no- 
