On the Seedling Structure of Gymnosperms. IV. 
BY 
T. G. HILL, F.L.S., 
Assistant Professor and Lecturer in Botany ; University of London ; University and 
Goldsmiths' Colleges. 
AND 
E. de FRAINE, F.L.S. 
University of London ; Goldsmiths' College. 
With Plates XXII and XXIII, and three Figures in the Text. 
GNETALES. 
Ephedra. 
T HE germination of the seeds of Ephedra has been described by 
Strasburger 1 and Bower 2 ; the latter author does not enter into the 
structure of the seedlings, but Strasburger draws attention to their mor¬ 
phology and the course of the cotyledonary and plumular bundles ; he 
also describes briefly the transition to root-structure, and remarks upon the 
close resemblance, in the transition phenomena, between Ephedra and 
Araucaria. Passing on to our own observations, the seedlings of the 
species of this genus examined, E. distachya, E. fragilis , E. campylopodia , 
and E. altissima } are indistinguishable one from the other, and are dicotyle¬ 
donous, epigeal, and linear in shape (PI. XXIII, Figs. 6 , 7 , and 8 ). At first 
the cotyledons are short, but ultimately they grow to a much greater 
length; thus seed-leaves ten centimetres long are not uncommon in 
E. fragilis. On the other hand the hypocotyl does not elongate to a 
corresponding degree, and it is very slender. 
The structure of the seed-leaves is very simple and calls for but little 
comment. The epidermis is covered with a cuticle which is very thin over 
the ordinary epidermal cells, but over the stomates, which are sunken below 
the general surface level of the leaf, it is considerably thicker. 
1 Strasburger: Die Coniferen und die Gnetaceen (Jena, 1872). 
3 Bower: The Germination and Embryology of Gnetum Gnemon (Q.J.M.S., xx, 1882). 
I Annals of Botany, Vol. XXIV. No. XCIV. April, 1910.] 
