ee 
— as ere 
1 
: 
1904] LAND—EPHEDRA TRIFURCA 15 
and gives rise to either three or four megaspores arranged in a row, 
the most deeply placed megaspore being functional. 
The nuclei resulting from the division of the megaspore show 
polarity in that they are definitely oriented with respect to the axis 
of the megasporangium. 
A vacuole appears between the nuclei resulting from the division 
of the megaspore before the spindle has disappeared, and soon becomes 
filled with delicate cytoplasmic structures which increase in density 
until walls appear. 
The free nuclei are parietally placed from the beginning, divide 
simultaneously, and are presumably 256 in number before walls 
appear. 
The female gametophyte is separated into two regions: a loosely 
formed archegonial region, and a more compact antipodal region, the 
latter being composed of a haustorial and a storage region. 
The archegonia vary from one to three, two being the usual num- 
ber; the neck is composed usually of eight tiers of cells; and there are 
no archegonial chambers. 
The apex of the nucellus breaks down, and a conspicuous pollen- 
chamber is formed. The necks of the archegonia are thus exposed 
to the air, and the microspores are brought directly into contact with 
the female gametophyte. 
No wall is formed between the ventral nucleus and the egg; the 
former becomes quite large and takes a position a short distance 
below the neck of the archegonium. 
The egg takes a position midway in the ieee of the archego- 
nium, surrounds itself with a membrane comparable to the one which 
invests the eggs of angiosperms, and in this position awaits fertilization. 
At the time of fertilization the cytoplasm in the archegonium has 
become almost homogeneous and: very dense, except in the region 
immediately below the neck of the archegonium, where it is loosely 
vacuolate. 
Thanks are due Professor John M. Coulter and Dr. Charles J. 
Chamberlain for criticism and advice; also Mr. O. B. Metcalfe, 
Mesilla Park, N. M., for efficient collecting of material. 
THE UNIVERSITY OF CHICAGO. 
