Studies on the Araceae. 
The Embryo-sac and Embryo of Aglaonema and 
Spathicarpa. 
BY 
DOUGLAS HOUGHTON CAMPBELL, 
Professor of Botany in the Stanford University , California , U. S.A. 
With Plates XXX, XXXI, and XXXII. 
EVERAL years ago a series of investigations were under- 
O taken upon the development of the embryo-sac and 
embryo in the Araceae. Some of the results of these studies 
have already been published 1 , but the investigations were 
interrupted for a time owing to pressure of other work, and 
have but recently been resumed. The present paper deals 
for the most part with two species, Aglaonema commutatnm , 
Schott, and Spathicarpa sagittaefolia , Schott. 
The earlier literature upon the development of the Araceae 
has been referred to in the writer’s previous papers, and will 
not be repeated here. A paper by Caldwell upon Lemna 2 
was omitted, but except for this the writer has seen no further 
contributions to the subject. 
The materials upon which the present paper is based were 
collected at the Royal Botanic Gardens at Kew, in August, 
1899. Through the kindness of the director, Sir W. Thiselton- 
Dyer, it was possible to obtain complete series of a number 
of species from the rich collection of Aroids in the greenhouses 
at Kew. Some of the material still remains to be investigated. 
1 Annals of Botany, xiv, March, 1900. 
2 The Life History of Lemna minor } Bot. Gazette, xxvii, Jan. 1899. 
[Annals of Botany, Vol. XVII. No. LXVIII. September, 1903.J 
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