Hill and de Fraine. — On the 
190 
states that if there are two cotyledons, the root is diarch ; if three seed- 
leaves are present, a triarch root-structure results ; but, if the number of 
cotyledons be more numerous, agreement between their number and the 
number of poles in the root no longer obtains. 
Dangeard was the first to work out in any detail the relationships 
between the cotyledonary strands and the root-structure ; his results are best 
expressed by the following quotation : ‘ Chaque faisceau de la racine, soit 
liberien, soit ligneux, s’insere sur deux traces cotyledonaires, ce qui peut 
'Zfl ’ 
etre indique par le rapport — . He then mentions some exceptions:— 
* 1. A ce que l’une des traces cotyledonaires se divise en deux pour 
donner insertion a un faisceau de la racine, les autres traces cotyledonaires 
conservent la disposition ordinaire : ce fait correspond aux rapports f , f , 
11 1_3 
6 > 7 • 
2. A ce que Tune des traces cotyledonaires se reunit a une autre sans 
servir a l’insertion : ce cas correspond aux rapports J, §, - 1 /-, \ 5 - \ 
It may here be remarked that these relations, according to our experi- 
ence, do not occur so regularly as the above indicates. Further, that on our 
hypothesis Dangeard’s first case i~~) corresponds to all the seed-leaves 
being half-cotyledons ; his second case corresponds to one seed-leaf being 
a whole cotyledon, and the rest half-cotyledons ; while his third case 
corresponds to one seed-leaf being a subsidiary cotyledon and the rest 
half-cotyledons. 
In a later paper Dangeard 1 describes many histological features in the 
seedlings of some Gymnosperms,and also transition-phenomena which will be 
referred to when necessary. 2 
Masters 3 described the morphology of the seedlings of many species, 
and showed how variable is the number of seed-leaves in one and the same 
genus. 
Tsuga. 
Tsuga canadensis , Carr. The normal number of cotyledons is appa- 
rently three, Masters 4 gives 3-5 as the range in number, and Dangeard 5 
1 Dangeard : Recherches sur les plantules des Coniferes (Le Botaniste, ser. 3, 1892). 
2 We did not discover the existence of this paper until after this present communication had 
been written, and it is for this reason that mention was not made of Dangeard’s work in our Part I 
(Annals, 1908). He briefly describes and illustrates the transition- phenomena in Cupressus funebris 
Endl., C. Corneyana Hort., C. Lindleyi Klotsch, A ctinostrobus pyrcimidalis Miq., Thuja orientalis 
L., and Taxus baccata, Tourn. We are in agreement with him in essentials ; but as regards details 
we have not found the bifurcation of the cotyledonary strand and rotation of the protoxylem quite 
so strongly marked in Thuia orientalis and Taxus baccata as he indicates. 
3 Masters : Comparative Morphology, Anatomy and Life-history of the Coniferae (Journ. 
Linn. Soc., Lond., Bot., xxvii, 1891). Notes on the Genera of Taxaceae and Coniferae. Id. xxx, 1895. 
4 Masters : 1895, loc. cit. 
5 Dangeard: Le Botaniste, iii, 1892. 
