Contribution to the life-history of Sequoia sempervirens. 
WALTER ROBERT SHAW. 
WITH PLATE XXIV. 
widely distributed genus of the Conifer. Each species is 
limited to a narrow natural distribution in California. We 
have no account of the development of the sexual generation 
(prothallium), our knowledge of the reproduction in this genus 
being limited to accounts of the development of the flowers’ 
and the germination of the seed? of S. sempervirens. The 
arboretum of Leland Stanford Junior University contains 4 
large number of young fruiting trees of the latter species. 1t 
also lies within the zone of distribution of the species, there 
being one tree one hundred and forty feet high on the unl 
versity grounds. Atthe suggestion of Dr. Douglas H. Camp- 
bell a study of the development of the macrosporang!@ 
(ovules) and the prothallia by microtome methods was be- 
gun in November, 1891, and carried on under his direction. 
The publication of the results was several times delayed 
hope of being able to make them more complete. ; 
The material for study was collected from young trees a 
the arboretum of Stanford University during the season © 
1891-92. Collections were made in December, 1891 (n0t 
dated), and from January 9 to July 5, 1892, at intervals of I ee 
to seven days. The young flowers were split longitudinally, 
and the sporophylls were removed from the older flowers. 
The specimens were fixed in 1 per cent. chromic acid od 
eighteen hours, washed in water, and transferred gradually 
with a solution of Bismarck brown in 70 per cent. alcohol, 49 
mounted in Canada balsam. 
1Strasburger, Die Angi : 8s. Jena, 1879: 
» “© Anglospermen und die Gymnospermen 85. 
*Strasburger, Die Coniferen und die Giietineen 307. Jena, ! 
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