lOO THE SCOTTISH BOTANICAL REVIEW 



The Embryo-Sac of Aglaonema. By Douglas 

 Houghton Campbell, 



Professor of Botaity in the Sianford University, California, U.S.A.^ 



(With Four Plates.) 



The Araceae constitute one of the most striking families of 

 monocotyledons, and although the greater number of these 

 inhabit the humid tropics, nevertheless they are represented 

 by a number of familiar species in the temperate regions ; 

 and the showy Caladiums, Calla lily, and others are familiar 

 ornamental plants. 



The simplicity of the floral structures suggests that the 

 Araceae may be primitive types, and several years ago the 

 writer began a series of investigations upon their floral struc- 

 tures in order to ascertain whether there were any indications 

 of primitive characters in the structures of the embryo-sac. 



Very little had been done previously upon the embryo-sac 

 of the Araceae except for the work of Hofmeister (i), published 

 over fifty years ago, when he described briefly the embryo- 

 sac and embryos of a number of species. The writer has 

 found no other references to the embryogeny of the Araceae 

 previous to 1900 except a series of papers by Hegelmeier (2), 

 in which was described the embryo of Pistia, and a third, 

 published by Mottier (3), on the embryo-sac of Ariscema 

 triphylluni. 



The writer has investigated more or less completely a 

 number of genera, mostly tropical types, collected in various 

 parts of the world, and some interesting peculiarities were 

 found to characterise most of these (4), (5), (6). 



Except for these papers the only recent contribution to 

 the subject, so far as we know, is a short paper on Symplo- 

 carpus {Spathyevia) (7). 



The genus Aglaonema comprises about ten species occur- 

 ring in the I ndo- Malayan region. They are plants of moderate 

 size with rather handsome leaves often flecked with white, 

 and they are sometimes cultivated for their foliage. They 

 are low, somewhat shrubby plants, the upright stems clothed 

 with oval lanceolate leaves with rather long petioles, and the 

 ^ Read before the Botanical Society of Edinburgh, 9th March 1912. 



