Berridge and Sanday. 
OOGENESIS AND EMBRYOGENY IN EPHEDRA 
DISTACHYA. 
BY 
Emily M. Berridge, F.L.S. and Elizabeth Sanday, B.Sc. 
[With Plates II. and III.] 
Introduction. 
M^HE investigation of spermatogenesis and embryogeny in this 
species of Ephedra was commenced as long ago as 1902 by 
Miss Sanday (then Research Student at the Royal Holloway 
College, at Dr., Scott’s suggestion. Almost the only sources of 
information concerning these important stages in the life-history of 
the genus up to that time were Strasburger’s observations scattered 
throughout his works on the Gymnosperms, and Jaccard’s very 
incomplete account for Ephedra helvetica. Through the kindness of 
Dr. Scott, Miss Sanday was able to secure material from a plant 
bearing male and bi-sexual strobili at Kew, which has furnished 
most of the details of spermatogenesis and of the early development 
of the embryo-sac recorded in this paper. 
In the summer of 1902 Miss Sanday made collections of 
material on the coast of Brittany at Fort Bloque, Gavres, and 
Ouiberon, which has been used for all the later stages in the 
development of the ovule from the differentiation of the young 
arehegonia Onwards. The material was gathered daily and some¬ 
times twice a day between the dates May 13th and June 20th, and 
fixed on the spot with absolute alcohol. Our thanks are due to 
M. Bertrand for his kind advice and assistance in this part of the 
work. During that year and the following nearly 250 slides were 
cut from this material, but, unfortunately, the investigation had to 
be laid aside owing to Miss Sunday’s departure for South Africa. 
After a second attempt in 1904 to work out the development of this 
species, which w r as again cut short by unforeseen circumstances, 
Miss Sanday, in November 1906, handed the slides, together with a 
few notes and some drawings made by Miss Benson, to the writer. 
In the meantime, however, Dr. Land’s paper on “ Spermatogenesis 
and Oogenesis in Ephedra trifurca” (1) had appeared. It was found 
that Miss Sunday’s slides in the main confirm Dr. Land’s results, 
hence the development of the ovule in its earlier stages and of the 
pollen-grain will be passed over somewhat rapidly, though some 
