2 20 
Hill and de Fraine. — On the 
Coming to more recent times, Sachs 1 made the following statement : 
‘The Taxineae and most Cupressineae and Araucarieae have two opposite 
cotyledons, although in some Cupressineae there are from three to nine, and 
in some Araucarieae whorls of four cotyledons ; while among the Abietineae 
there are rarely so few as two, more often four, or even as many as fifteen. 
To refer this larger number of cotyledons to the division of two opposite 
ones, as Duchartre proposes, is entirely opposed to the other processes 
of leaf-formation in these plants, especially to the common occurrence 
of whorls consisting of several leaves on the growing axis of seedlings.’ 
This disbelief was seemingly shared by Masters , 2 who, after mentioning the 
opinion of Adanson and his followers, remarked : ‘ If, however, the vascular 
bundles be traced from the caulicle [hypocotyl], it will be seen that the 
vascular cylinder breaks up not first into two divisions, which subsequently 
branch, but into a variable number not always in direct relation to the 
number of cotyledons.’ 
Dangeard 3 recognizes that polycotyledony may have arisen either 
by the intercalation of members of the first foliage whorl between the 
existing cotyledons, or by the splitting of the original seed-leaves. He 
examines both hypotheses, and, discarding the former, he says, ‘ Nous 
pensons que l’augmentation du nombre des cotyledons chez les Gymno- 
spermes provient de la division de deux larges cotyledons ; cette transforma- 
tion s’est effectuee, dans la serie des temps geologiques, sur un type voisin 
des Araucaria : mais ces deux cotyledons ont perdu actuellement toute 
individuality, elle s’est fragmentee pour ainsi dire en nouvelles individualites 
bien caracterisees.’ 
Clearly botanical opinion is divided, and it must be owned that the 
proof advanced in support of the contention of Adanson and Jussieu leaves 
much to be desired. 
We may now pass on to the examination of our own evidence. 
The Taxeae, Podocarpeae, and many of the Cupressineae, are charac- 
terized by the possession of two cotyledons ; each of them, with the exception 
of those of the Podocarpeae, has a single vascular bundle which undergoes 
a bifurcation and a more or less well-marked rotation of the xylem elements 
to produce one pole of a diarch primary root. The Abietineae, with the 
exception of the Araucarieae, are tri- to polycotyledonous ; each seed-leaf 
again has a single vascular strand, with certain exceptions which will be con- 
sidered below, but the primary root may be diarch, triarch, tetrarch, and so 
on, the number of poles bearing no obvious relation to the number of 
cotyledons , 4 a feature which has struck more than one observer . 5 The 
1 Sachs : Textbook of Botany, 2nd ed. (Oxford, 1882, p. 507). 
2 1891, loc. cit. 
3 Dangeard: Plantules des Coniferes (Le Botaniste, ser. 3, 1892, p. 196). 
4 See the table at the end of this paper. 5 Van Tieghem, Chauveaud, &c., op. cit. 
