SPERMATOPHYTES—GYMNOSPERMS 
289 
The Embryo.—The early stages of the sporophyte, usually 
designated as the proembryo, have been mentioned already. 
From the time when the suspensors begin to elongate up to the 
appearance of cotyledons, instructive preparations can be made by 
mounting the embryo whole. Dr. J. T. Buchholz has developed a 
method for handling these small objects. Remove the testa and 
then, under water, hold the endosperm gently with forceps and 
press the neck and upper part of the archegonium with a needle, 
pressing, and at the same time drawing the needle away, so as to 
pull the young embryo out. Some of the embryos will be broken, but 
by careful manipulation more than half should be entirely uninjured. 
Fix in formalin (5 per cent in water), stain in Delafield’s haematoxylin, 
transfer to 10 per cent glycerin, and continue with the Venetian 
turpentine method. A preparation made in this way is shown in 
the photomicrogaph (Fig. 103). 
These stages, and all subsequent stages, are easily cut in paraffin 
without removing the embryo from the endosperm. Cut a thin 
slab from opposite sides of the endosperm, fix in chromo-acetic acid, 
with or without a little osmic acid, imbed in paraffin, and stain in 
safraqin and gentian-violet. This will give a good view of the abun¬ 
dant starch and other food stuff, «,nd at the same time will bring out 
sharply the cell walls of the embryo. 
GYMNOSPERMS—GNETALES 
Of the three peculiar genera belonging to this order only one, 
Ephedra, occurs in the United States. Welwitschia is found only in 
Damaraland, South Africa, and Gnetum is tropical and subtropical. 
Gnetum thrives in the greenhouse, but the other two have not been 
cultivated successfully. All show vessels in the secondary wood, an 
angiosperm character. The strobili can be fixed in formalin-alcohol- 
acetic acid, but in Ephedra the dry chaffy scales must be dissected 
away before completing the dehydration and infiltration with paraffin. 
If you can secure material of Ephedra, Dr. Land’s researches 1 pre¬ 
sent a very complete life-history, with dates of various stages and 
suggestions for fixing and staining. 
1 Botanical Gazette , 38:1—18, 1904, and 44:273—292, 1907. 
