164 ON SOUTH-AMERICAN APOCYNACEA, 
HOMALADENIA*, nob. : Dipladenia (in parte) auctorum. Sepala acuta vel longe acuminata, imbricata, intus 
squamulis 2 minimis ad basin munita. Corolla hypocrateriformis ; tubus tenuiter cylindricus, ad 
faucem vix latior; segmenta rhomboideo-dolabriformia, triplo breviora, rotata, dextrorsum convoluta. 
Stamina intra faucem inclusa, sepe ex annulo niveo-piloso orta ; filamenta pilosa ; anthere his duplo 
longiores, apice acutee, imo breviter cordate, in conum conniventes. Discus opposite bilobus, lobis 
anguste oblongis. Ovaria 2, acuta, his alterna et paullo longiora ; stylus tenuis ; clavuncula incrassata, 
5-sulcata, imo membrana peltata indusiata; stigmata 2, parva, terminalia. Folliculi 2, tenuiter 
teretes, subtorulosi, erecto-patentes. Semina plurima, oblonga, sæpe pilosa; coma dupla, erecta, pilis 
inferioribus duplo longioribus, exterioribus multo brevioribus; emóryonis radicula supera. 
Suffrutices valde humiles, Brasilienses vel Guianenses : radix crassa, dauciformi-tuberosa, apice caulos 
plurimos emittens; caulis simplex, sepius. tenuissimus, erectus, imo nudiusculus, apicem versus crebre 
foliosus; folia opposita, anguste linearia aut lanceolato-oblonga, erecta, imbricata, rarius remotiora, 
brevissime petiolata ; racemus terminalis, pauciflorus ; flores parvi, rarius mediocres. 
1. HomaALADENIA TENUIFOLIA, nob. : Dipladenia tenuifolia, A. DC. Prodr. viii. 482 : Dipladenia polymorpha, 
var. tenuifolia, Müll. Fl. Bras. xxvi. 121: Echites tenuifolia, Mikan, Flor. Bras. fasc. 3; Stadelm. 
Bot. Zeit. 1841, p. 53. In Brasilia, prov. Rio de Janeiro, Minas Geraés et Goyaz: v. s. in herb. 
meo prov. Goyaz (Gardner 3888). 
A species with an erect filiform stem, 6-9 in. high, bare at its base, sending out a short 
lateral branchlet; axils ¿-1 in. apart; leaves opposite, narrowly linear, subincurved, 
acuminate, fleshy, margins revolute, glabrous anor: puberulous beneath, 14-24 in. long, 
barely 3 line broad, on petioles 1 line long; raceme terminal ; pe bearing 4 
alternate flowers 6-9 lines apart, on pedicels 34 lines long, with basal bracteoles 1 line 
long; sepals acute, 1 line long; tube of corolla very slender, 6 lines long, a little swollen 
at the mouth, within which the stamens are enclosed ; segments obliquely oblong, rotate, 
3 lines long, 2 lines broad; the glabrous follicles (which I have not seen) are 4 in. long, 1 
line broad, scarcely torulose ; seeds 4 lines long ; coma, outer row 6 lines long, inner series 
12 lines long. 
A drawing of this plant, in flower and in fruit, is shown in Plate XXIV a. 
2. HoMALADENIA LINARI#FOLIA, nob.: Dipladenia linariefolia, A. DC. l. c. p. 482. In Brasilia, prov. 
Bahia : non vidi. 
A slender stem 4-5 in. high, hirsutely puberulous, throwing out other branchlets from 
its base; leaves narrowly linear, obtuse at the base, acuminate, rigid, with revolute mar- 
gins, subglabrous, 1-13 in. long, à line broad, erect; terminal peduncle 1-14 in. long, 
bearing about 3 flowers, on pedicels scarcely 4 line long; sepals subulately lanceolate, 
3 lines long; tube of corolla 7-8 lines long, very slender, thicker in the mouth, within 
which the stamens are enclosed, seated on a pilose ring; segments obliquely oblong, 4 
lines long, 2-23 lines broad. 
3. HOMALADENIA PASTORUM, nob.: Dipladenia pastorum, A. DC. l. c. p. 482: Dipladenia palymorpha, var. 
tenuifolia, Müll. l. c. p. 121: Echites pastorum, Stadelm. l. c. p. 52: v. s. in herb. meo Minas Geraés 
(Claussen 256). 
A tuberous root, throwing out several slender, puberulous, simple stems, 6 in. high, 
* From éua\ds (planus), ádyv (glans), from the flat shape of the lobes of the disk, 
