224 
Hill and de Fraine. — On the 
SUMMARY. 
Cotyledons. 
1. The number of cotyledons varies : the hypogeal species of Araucaria 
have two, the epigeal also have two, which may be divided so deeply as to 
form apparently four ; Tsuga seldom has more than three ; the species 
of the other genera examined may have from three upwards (see table 
below). 
2. Some of the seedlings possess a more or less well-marked cotyle- 
donary tube, e. g. Pinus Pine a, P. canariensis , P. contorta , var. Murray ana , 
P. montana , var. gallic a, P. sylvestris, Abies pectinata , A. amabilis , Pice a 
ajanensis , Cedrus atlantica , and C. Deodara. In the following plants 
certain of the cotyledons fuse laterally at their bases so that an incomplete 
tube is produced, Pinus Pinea , P. Gerardiana , P. halepensis , P. australis , 
P. insignis , P. contorta , var. Murray ana, P. montana , var. gallic a, P. sylve- 
stris , Larix , Abies sibirica, and Pice a morinda . 
3. Some seed-leaves exhibit a longitudinal split from the apex towards 
the base, e. g. Cupressus tortdosa , Abies sibirica , and Pinus montana , var. 
gallica. This division is constant and extends almost to the base in 
Araucaria Cunninghamii. 
4. Resin ducts are generally present. In the following, each cotyledon 
has two canals situated one at each dorsal corner, A. sibirica , yl. Veitchii , 
A. balsamea , A. amabilis , A. magnifica , var. Shastensis , Cedrus Deodara , 
Pinus Pinea , P. Gerardiana , P. canariensis , Larix europaea , L. leptolepis , 
and Pseudolarix Kaempferi. In the following plants, each seed-leaf has 
one resin duct, situated in the mesophyll immediately dorsal to, or by the 
side of (in the case of half-cotyledons), the vascular bundle. Pinus australis , 
P. insignis , P. contorta , P. contorta , var. Murray ana, P. montana , var. 
gallica , and P. sylvestris. 
The Araucarias have several resin ducts in their cotyledons, while 
in the following plants no such canals have been observed : Tsuga, Abies 
pectinata, Picea, Pinus halepensis , P. Coidteri, and Larix occidentals. 
Resin-ducts are absent from subsidiary cotyledons and many half- 
cotyledons. 
5. The mesophyll is, without exception, homogeneous. 
6. The seed-leaves of Araucaria each contain several bundles (4-8), 
those of Tsuga, Abies, Picea, Cedrus, Pinus, and Larix each have one 
vascular bundle. 
Exceptions, however, occur ; one cotyledon of a seedling of yl. 
ninghamii had three strands ; two vascular bundles occurred in the 
cotyledons of a few seedlings of Pinus contorta, var. Murray ana, P. montana, 
var. gallica, and Larix europaea . 
