The Gametophytes and Embryo of Sciadopitys 
verticillata. 
BY 
A. ANSTRUTHER LAWSON, Ph.D., F.R.S.E. 
Lecturer in Botany , the University of Glasgow. 
With Plates XXIX-XXXI. 
O UR knowledge of the gametophytes and embryo of Sciadopitys is very 
meagre, consisting essentially of a brief and fragmentary account 
of the mature archegonium and embryo published by Professor W. Arnoldi 
in 1901, and Thomson’s description of the megaspore membrane. I have 
thought it worth while to prepare a fuller account of the developmental 
stages in connexion with the gametophytic structures, fertilization, and 
embryo of this interesting genus, in the hope of filling a gap in our 
knowledge of the Coniferales as a whole. 
All of the material for this investigation was obtained from young 
trees growing in the Pinetum of the Royal Gardens, Kew. P"or facilities 
afforded in collecting material and also preparing it in the Jodrell Labora¬ 
tory, I am much indebted to the Director, Lieut.-Col. Prain, F.R.S. I am 
also very much indebted to Mr. L. A. Boodle, F.L.S., for many kindnesses. 
Circumstances did not permit of my remaining at Kew sufficiently long to 
obtain all of the necessary material, but Mr. Boodle was kind enough 
to send me living cones from time to time; without this help many of the 
interesting stages would, of necessity, have been omitted. 
The Male Gametophyte. 
From the material collected at Kew Gardens it appears that the micro¬ 
spores mature early in April, and pollination occurs between two and three 
weeks later. At maturity the microspores have a very thick, hard, re- 
sistent exine or exospore, and a well-developed but thin endospore. 
The thick, hard, outer membrane offered such resistance to the knife in 
cutting that it was impossible to obtain very thin sections of the micro¬ 
spores. Sections, however, were obtained sufficiently thin to make out all 
of the essential details. As shown in PL XXIX, Figs. 1, 2, 3, and 4, the 
endosporium appears to be very thick, but this appearance is due to the 
[Annals of Botany, Vol. XXIV. No. XCIV. April, 1910.] 
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