138 ON SOUTH-AMERICAN APOCYNACEZ. 
RHODOCALYX. 
This genus comprises several low-growing plants, for the most part springing out of 
ligneous tuberose rhizomes, producing several short stems, knotty and bracteolate at the 
base, bare and erect above, where they are furnished with few opposite broadish leaves, 
either subsessile or petiolate. The inflorescence consists of one or few flowers, axillary 
or terminal in the sinus of the two ultimate leaves; these are supported by slender pedi- 
cels, bracteolate at the base; the sepals are rather large, often of a reddish hue, sub- 
membranaceous, reticulately veined, acute, sometimes subcordate at the base, with an 
inner, broad, deeply lacinulate scale; the corolla is salver-shaped ; tube narrowed at 
the base for the length of the calyx, funnel-shaped above; segments oblong, one-third 
of its length, with dextrorse convolution ; stamens seated in the constriction of the tube ; 
anthers linear, acute, subcohering, with 2 short basal prongs; style filiform; clavuncle 
thickened, cylindrical, with a basal peltiform appendage. But the chief peculiarity is 
the manner in which its seeds are suspended from the lamellar placente of 2 terete 
follicles; these are imbricate, oblong, subcompressed, dorsally convex and cancellately 
reticulated, concave on the ventral face, where they are marked with a raphe running 
from top to bottom, which at its summit is extended into a filiform funicle 6 times 
the length of the seed, and by which the latter is suspended from the placenta; the 
seed is crowned by an erect coma 5 times its length; the anatropous embryo is im- 
bedded in albumen, its 2 oblong foliaceous cotyledons, laterally incurved, are 3 times 
as long as the more slender terete superior radicle. 
The presence of a distinct funicle, by which the seed is suspended, brings this genus 
into proximity with Stipecoma; but it wants the long peculiar rostrum, seen in the seed 
of the latter genus ; in other respects it is extremely different. 
1. Ruopocatyx ROTUNDIFOLIUS, Müll. Fl. Bras. xxvi. p. 173, tab. 51. In Brasilie prov. central. : v. s. 
in herb. meo, Minas Geraés (Claussen). 
This plant, in the herbarium, may at first sight be mistaken for the Dipladenia illus- 
tris, var. rotundifolia, of Miller; but it may be recognized by the presence of its lower 
bracteiform leaves, by its smaller flowers, larger (not lanceolate) sepals, a shorter tube 
of the corolla, which is a little longer than the sepals. It has been wrongly regarded as 
identical with the Zehites erecta of Velloz (which is Laseguea erecta, Müll.). Its ligneous 
rhizome is horizontal, sending from one extremity several short erect stems, scarcely a 
foot long, bearing towards the base a few opposite acute bracteiform scales (abortive 
leaves), and, above the middle, 2 or 3 pairs of leaves about 2 in. apart; the leaves are 
suborbicular, with a very short acumen, pale green above, thickly clothed with a whitish 
tomentum, with about 4 pairs of distant immersed nerves, 13-23 in. long, 14-23 in. 
broad, with a pubescent petiole 1 line long. The inflorescence is tomentous, 2-43 in. 
long, on a straight peduncle bearing about 4 pairs of opposite flowers (sometimes 
reduced to a single one) on pedicels 10 lines long, each furnished at the base with a bract 
nearly of its length, acutely oblong, glabrous, with ciliated margins; sepals oblong, 
