The Gametophytes and Embryo of Pseudotsuga 
Douglasii. 
BY 
ANSTRUTHER A. LAWSON, Ph.D. 
Lecturer in Botany , the University of Glasgow. 
With Plates XII, XIII, and XIV. 
D URING an examination of the gametophytic structure of various 
genera of the Abietineae certain features in regard to Pseudotsuga 
Douglasii were brought to light which proved to be unusual and interesting. 
On account of the accumulating evidence in support of the view that the 
Abietineae constitute a very ancient group of the Coniferales, and especially 
as Pseudotsuga is one of the few genera which have not been investigated, 
it has been thought advisable to record these unusual features in connexion 
with the gametophytes of this genus. 
The material was collected in Santa Clara County, California. The 
investigation was, for a considerable part, carried on at the Jodrell 
Laboratory, Royal Gardens, Kew, but was finished in the Laboratory 
of the University of Glasgow. For facilities afforded at the Jodrell 
Laboratory I am much indebted to Lieut.-Col. Prain, F.R.S., and also 
to Mr. L. A. Boodle, F.L S., for many kindnesses. 
The Male Gametophyte. 
Pollination takes place early in April or the latter part of May, and 
lasts for two or three weeks. The first material for the study of the micro- 
spores was collected on April 2. At this date many of the sporangia 
at the base of the cones had discharged their microspores, but the sporangia 
in the middle and upper regions of the cones were quite full of pollen. There 
appeared to be no difference in the state of development, however, between 
the microspores within the sporangia at this time, and those which had been 
discharged. The spores were practically globular in form, and showed 
a distinct and well-developed exine. Unlike Cedrus , Pinus, and many other 
Abietineae, there were no wings or bladder-like swellings to give buoyancy 
to the spore. A cross-section of a microspore at the time of pollination is 
[Annals of Botany, Vol. XXIII. No. XC. April, 1909.] 
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