SYSTEMATIC ARRANGEMENT OF THE SPECIES OF THE GENUS CUSCUTA, WITH 
CRITICAL REMARKS ON OLD SPECIES AND DESCRIPTIONS OF NEW ONES. 1 
From the Transactions of the Academy of Science of St. Louis, Vol. I. No. 3, 1859. 
The genus Cuscuta belongs to the natural order of Convolvulacece, to which, indeed, it has been 
attached by almost every botanist, and from which it cannot be separated, though the embryo is very 
distinct, being rather a minute plant than an embryo in the usual form, the tip forming a plumula, 
often provided with alternate scales, and without cotyledons proper. Nor ought such a natural 
group of plants to be split into a number of genera on subordinate characters, as has lately been pro¬ 
posed, and in some instances, too, upon erroneous observations. 
The characters which furnish good grounds for a subdivision of the genus are found in the 
shape of the styles and stigmata and in the fruit. These same characters, it must be admitted, have 
been used in separating the old Convolvuli into numerous genera, and even tribes ; so that analogy 
would justify or even require a similar division of Cuscuta ; but even Choisy, the author of many of 
these new convolvulaceous genera, in his Monograph and in De Candolle’s Prodromus, admits the 
propriety of keeping Cuscuta united. Splitting Convolvulus into numerous genera may be excused, 
or perhaps justified by the necessity of separating the large crowd of species into a number of groups. 
This law of expediency, however, can have no scientific value, and can certainly not be pleaded in 
regard to such a natural, easily recognized, and not too numerous genus, as Cuscuta is. 
The subdivisions proposed are based, as has been stated, on the shape of the styles and stigmata, 
and on the capsule. 
The styles , typically always two, usually are distinct; or they are united in their whole length, 
or nearly so. They are of equal thickness throughout, or are thicker at base (subulate), or thickened 
towards the top (club-shaped); they are of equal length in one group, and unequal in another. 
The stigmata are cylindric, elongated, and of the same thickness as the styles, or thinner; or 
they are oblong, or oblong-elongated, and thicker than the styles; or they are subulate from a thick 
base; or we find them capitate (or, as they are often, though wrongly, called, globose), hemis¬ 
pherical, or somewhat flattened on the upper, and flattened or usually impressed at the lower surface 
at the insertion of the style. In a single species, the stigmatic surface of the dilated top of the style 
is lobed, and in the centre somewhat depressed. 
The capsule is either circumscissile, opening transversely by a regular joint, with [454 (4)] 
thickened edges; or it bursts transversely with an irregular, jagged margin; or it remains 
closed (it is baccate, as it is termed), and either falls out of the persistent calyx, or it finally falls off 
with the calyx. 
1 See also Latin translation by Ascherson, with preface by A. Braun, published under title “ Generis Cuscutse species 
secundum ordinem systematicum dispositse adjectis in prius jam notas observationibus criticis nec non novarum descriptionibus, 
auctore Georgio Engelmann, M.D.” Berlin, 1860; pp. 8 -J- 87. — Eds. 
Mo. Bot. Garden 
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1 142, fig. 14) are taken from unripe seeds. 
Annf.hpT» nha t , 
uo °y vveDD, Jfnyt. Can. III. pi. 
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