72 SYSTEMATIC ARRANGEMENT OF THE SPECIES 
Between both styles of the ripe and dry capsule an opening is observed — the intrastylar aper- 
ture — parallel with or transverse to the dissepiment, more or less rhombic, formed by an incomplete 
separation of both carpels, which compose the capsule. This separation takes place in that triangular 
and thickest part of the dissepiment which lies next to and below the styles, and which, in the species 
with circumscissile fruit, adheres to the top, while the greater and thinner obcordate or bilobed part 
of the dissepiment remains attached to the base of the capsule in the bottom of the calyx. 
In most instances the stylar portions of the dissepiment, as I will call this part, remain united 
at base, separating the funnel-shaped intrastylar aperture from the interior cavity of the capsule, and 
therefore cannot give egress to the seeds, as has been erroneously stated. This is, I believe, the case 
with most or all American Cuseute (Grammica). In Kucuscuta and Epistigma the intrastylar 
aperture does communicate with the cells of the capsule, but the opening is far too small to let the 
seeds out ; nor would this be necessary, as in all of them the capsule is circumscissile. In some few 
species I find each stylar portion of the dissepiment divided into two halves; in C. pedicellata these 
halves are widely distant from one another and adhere to the opposite halves, so as to form an 
opening into the capsule transverse to the dissepiment. 
In Monogynella and Callianche, where the styles are united, there is, of course, no intrastylar 
opening, and in the former the entire dissepiment remains in the bottom of the capsule; in the 
latter, a small triangular stylar portion adheres to the top of the capsule, but, of course, without any 
opening. 
Des Moulins was the first, in his “ Etudes,” to draw attention to the shape of the seed in general 
and the direction of the hilum in particular. Where all the four seeds are well developed, they are 
triangular, with a larger exterior convex and two smaller flat surfaces, the latter facing the dissepi- 
ment and the other seed of the same cell; the top of the seed is rounded or acutish; the base, with 
which it is attached to the placenta (which itself is dilated into a disc, often cup-shaped), is obliquely 
truncate or somewhat hooked, or rostrate, as Des Moulins terms it. Both flat faces of the seed are 
equal, or the one directed towards the dissepiment is larger than the other. At the truncate base of 
the seed, in the centre of a smooth and roundish umbilicus, is the hilum, forming a longer 
or shorter, narrower or broader linear groove, sometimes reduced almost to a point; itruns [455 (5)] 
in the direction of the interior angle of the seed (longitudinal, DesM.), or at right angles 
with it (transverse, DesM.), or it has an intermediate, oblique direction. In some sections I find these 
characters sufficiently distinct ; in others they seem to be less reliable; in the American Cuscute I 
have often found them intermediate, and variable, often in seeds from the same capsule. Wherever 
only one or two seeds in a capsule come to maturity their shape becomes less distinct; and offers no 
good characters. It is scarcely necessary to add that only ripe seeds ought to be examined ; unripe 
ones, especially when pressed hard, have led to the strangest mistakes ; winged or margined seeds 
described by authors are such unripe seeds. Nearly ripe seeds are smoother and larger, when soaked, 
than ripe ones. 
The embryo has been supposed to offer good characters; but I have reason to believe that those 
embryos with one or few circumvolutions (such as the one figured by Webb, Phyt. Can. III. pl. 
142, fig. 14) are taken from unripe seeds. 
Another character which I at one time relied on for generic distinction of Cuscute is found in 
the calyx. Usually it is gamosepalous, but in some American species it is formed of entirely dis- 
tinct and imbricate sepals, not different from the surrounding bracts, —a character which prevails in 
Convolvulacee proper, where only one genus (Wilsonia) is gamosepalous. 
The specific characters of Cuscute are found in the thickness of the stem, but principally in the 
inflorescence and in the different organs of the flower and fruit. 
The inflorescence together with the presence or absence of bracts within it offers good characters ; 
less so, the presence or proportion of pedicels. 
