158 ON SOUTH-AMERICAN APOCYNACEZ. 
MICRADENIA. 
A series of plants, first placed in a group distinct from Dipladenia by Prof. DeCandolle 
in 1844. These are distinguished from the former by their habit, especially in the incras- 
sated axils of the branches, furnished with a whorl of warty glands between the petioles, 
in the pedicels of the flowers spirally twisted, in the anthers with long, obtuse, parallel, 
basal prongs, in the much shorter disk, seldom attaining more than a quarter of the length 
of the ovaries, in the incrassated placenta of the follicles, from which are suspended many 
flat imbricate seeds having a nearly obsolete coma of short scale-like hairs. It forms 
a very good genus, well-marked by constant and uniformly peculiar characters. 
Micrapenta, A. DC.: Sepala 5, subparva, valde acuminata, quincuncialiter imbricata, intus ad basin 
squamulis 2 bidentatis munita, persistentia. Corolla majuscula; tubus glaber, pro 1 parte crassior 
angustissime cylindricus, dein ampliatus, cylindrice campanulatus, ssepius submembranaceus; seg- 
menta 5, rhomboideo-dolabriformia, latere mucronata, tubo seepius 3plo breviora. Stamina ad con- 
tractionem tubi in annulo piloso inserta ; filamenta subbrevia, niveo-pilosa; anthere lineari-oblonge, 
acute, basi in furcas 2 obtusulas parallele lineares fisse. Discus e lobis 2 oppositis, brevissime 
latis, rotundatis, quam ovaria seepius 4plo brevioribus. Ovaria 2, acute oblonga, lobis disci alterna; 
stylus tenuis, imo fissus, cruribus cum ovario articulatis ; clavuncula incrassata, 5-sulcata, imo mem- 
brana peltata indusiata, ad antheras cohærens ; stigmata 2, minima, acuta, terminalia. Folliculi 2, 
erecti, curvati, teretes, sutura ventrali dehiscentes, marginibus introflexis in placentam eylindricam 
coalitis ; semina plurima, parva, compressissima, obspathulata, raphe tenui sequilonga summo sus- 
pensa; comu brevissima, e pilis paucis brevissimis, subpaleaceis. 
Suffrutices Brasilienses, ramosissimi ; rami subsarmentosi, sepe fleauosi; axille sepe approximate, 
valde incrassate, glandulis plurimis carnosis verticillatim munite ; folia opposita, elliptico-oblonga, 
sepius longiuscule petiolata; racemi axillares vel terminales, pauciflori ; flores speciosi, albi, rosei vel 
atro-purpurei; pedicelli spiraliter torti. 
l. Micrapenra CRASSINODA, A. DC. L c. p. 486: Echites crassinoda, Gardn. Lond. Journ. Bot. i. 544: 
Dipladenia crassinoda, Müll. (non Lindl.) J. c. p. 132. — In Brasilia, prov. Rio de Janeiro: v. v. in 
summo Monte Corcovado: v. v. et sicc. in herb. meo (3137); in hb. Mus. Brit.; v. s. ex eodem loco 
(Gardner, 250). 
I collected this plant in 1836, in company with Gardner. It is of low growth, with 
many straggling, sarmentose, stout branches, subfistulose, covered irregularly with a 
lax epidermis, somewhat corrugately striate, very incrassate in the approximate axils, 
which are only 3-6 lines apart, 3-4 lines broad, bearing on each side, between the 
petioles, 4-6 subulate warty excrescences, often pectinately combined together; leaves 
lanceolate-oblong, acute at both ends, glabrous, subcoriaceous, green above, with semi- 
immersed divergent nerves, beneath ferruginously opake, with immersed nerves, 24-33 
in. long, 5-12 lines broad, on slender channelled petioles 2 lines long; axillary racemes 
133 in. long, with a bracteolated peduncle 9 lines long, bearing about 5 alternate white 
flowers, on spirally twisted pedicels 6-9 lines long, obsoletely bracteolated at the base; 
_sepals lanceolate, sharply acute, with pellucid margins, having within 2 bifurcate basal 
scales ; tube of corolla 2 in. long, narrowly cylindrical at the base for a length of 4 lines, 
funnel-shaped above, with subtruncate, dolabriform segments 10 lines long, 9 lines broad ; 
stamens 4 lines long, inserted at the contracted portion of the tube, on a densely pilose 
