COMPARISON OF DEVELOPMENT IN DODDER AND 
MORNING GLORY‘ 
GERTRUDE ELIZABETH MACPHERSON 
(WITH PLATES XXV—XXVII) 
The embryo of Cuscuta Gronovii Willd. is described in BRITTON 
and Brown’s Flora of the Northern United States and Canada as 
follows: ‘“‘Embryo linear, terete, curved or spiral, its apex bearing 
1-4 minute scales; endosperm fleshy, cotyledons none.” The 
purpose of this study was to determine whether there might not 
be at least a trace of cotyledonary development. In examining 
embryos of Cuscuta, which is a parasite, for indications of a rudi- 
mentary development of cotyledons, it seemed desirable to make 
a comparison with some non-parasitic species of the same family, 
and Convolvulus sepium L. was selected for this purpose. 
By far the larger number of previous studies of Cuscuta have 
been concerned with the physiology of the plant, its host relation- 
ships, or geographical distribution, and few with the life history 
and morphology. Miss Hooker mentions the presence of scales on 
the inner and outer surface of the curve of the coiled embryo, but 
states that their position does not justify considering them cotyle- 
dons. The remainder of her paper discusses the habits of grow 
of Cuscuta Gronovii. CovuLteR and CHAMBERLAIN,? in discussing 
the endosperm, remark that, contrary to the usual course of 
development in parasites, the endosperm of Cuscuta is formed by 
free nuclear division, and later in treating of the types of embryos 
in Angiosperms they state that the embryo of Cuscuta is also an 
exception to the morphology of parasites in that it is large and 
well developed. These are the only important references to the 
embryo of Cuscuta that have come to the writer’s attention. 
Paper no. 14 of the technical series, New Jersey Agricultural Experiment 
Station, department of plant pathology. 
2 Hooker, Henrtetra E., On Cuscuta Gronovii. Bot. Gaz. 14:31-37- 1899- 
3 CouLTer, J. M., and CHamBertatn, C. J., Morphology of angiosperms. 
Chicago. 1903 (pp. 174, 176). 
Botanical Gazette, vol. 71] [392 
