oe .—- a 
ZYGOCACTUS. 177 
Subtribe 7. EPIPHYLLANAE. 
Mostly epiphytic and night-blooming cacti, generally growing on trees, but sometimes on the 
earth when this is rich in humus, rarely in the crevices of rocks, much branched, spineless (except 
Eccremocactus and some species of Epiphyllanthus); joints several or many, usually flat except at 
base, often thin, with the areoles borne along the margin (except in Epiphyllanthus); flowers 
regular (except in Zygocactus and Epiphyllanthus); perianth various; filaments usually long and 
slender; style long and slender; fruit spineless, usually red or purple, either naked or bearing a few 
scales (rarely many), these usually with naked axils; seeds small, black. 
We recognize 9 genera, diverse both in the plant-body and in the flowers. While 
apparently riot closely related among themselves, the genera forming this subtribe are not 
any more closely related to other genera, either in the Cereanae or in the Rhipsalidanae. 
KEy TO GENERA. 
Plants branching dichotomously. 
Perianth irregular. 
Joints thin and leaf-like with toothed margin; areoles all marginal............ 1. Zygocactus (p. 177) 
Joints thick, without teeth, bearing areoles all around. .................2.0.. 2. Epiphyllanthus (p. 180) 
Perianth regular or nearly so; joints thin.........00... 0.0. c cece cece tence eunees 3. Schlumbergera (p. 182) 
Plants branching irregularly. 
Perianth-segments spreading or reflexed; flowers mostly large. . 
Tube of flower definitely longer than limb. ............. 002 0c. cece ee eeeeues 4. Epiphyllum (p. 185) 
Tube of flower not longer than limb. 
Perianth campanulate, its segments few. : 
Stamens few; flowers small........ 0.0.0.0. ccc cece e cece ee ee ee eee 5. Disocactus (p. 201) 
Stamens many; flowers large.............. cece cece cece ee cceeeeees 6. Chiapasia (p. 203) 
Perianth short-funnelfornm, its segments many. , . . 
Outer perianth-segments short, obtuse or rounded, the inner white... 7. Eccremocactus (p. 204) 
. Outer perianth-segments acute or acuminate, the inner rose or red.... 8. Nopalxochia (p. 204) 
_Perianth-segments erect; flowers small. ........0 00.0. c cece eee e cece eee eee e eens 9. Wittia. (p. 206) 
| / 3) (] 1. ZYGOCACTUS Schumann in Martius, Fl. Bras. 4°: 223. 1890. 
Stems dichotomously much branched, flattened, divided into short joints; flowers terminal, 
polychromic, irregular; ovary terete, smooth, gradually broadening from base, bearing minute 
Scales at top; flower-tube abruptly bent just above the ovary, ending in a serrate mouth, bearing 
petaloid spreading scales scattered along its sides; stamens slender, white, arranged in 2 clusters; 
outer stamens borne along inside of flower-tube from near base to near middle; inner clusters of 
Stamens about 20, arising from center and forming a short tube about base of style with an inner 
deflexed toothed membrane, upper part free, and all appressed against upper side of flower-tube 
and upper perianth-segments; style purple, slender, as long as stamens and usually not surrounded 
by them; stigma-lobes linear, purple, erect and adhering (so far as we have seen); fruit purple, 
turgid, not at all angled; skin thin; seeds dark brown to nearly black, shining. 
Type species: Epiphyllum truncatum Haworth. 
This genus has passed for many years under the name of Epiphyllum but that name 
was wrongly applied to it. One species is here recognized, although several have been pro- 
posed by previous authors. 
The generic name is from ¢uyév yoke and xaxros cactus, referring, doubtless, to the 
peculiarly jointed stems. 
~~ 1. Zygocactus truncatus (Haworth) Schumann in Martius, Fl. Bras. 47: 224. 1890. 
Epiphylium truncatum Haworth, Suppl. Pl. Succ. 85. 1819. 
Cactus truncatus Link, Enum. Pl. 2:24. 1822. 
Gorens truncatus Sweet, Hort. put Alan aB26, AE 
tphyllum altensteinii Pfeiffer, Enum. Cact. 128. . 
Ebipholium truncatum altensteinit Lemaire, Cact. Gen. Nov. Sp. 76. 1839. 
Epiphyllum purpurascens Lemaire, Hort. Univ. 2: 349. 1841. 566 
Epiphyllum truncatum violaceum Morren, Belg. Hort. 16: 260. — 
Epiphyllum truncatum spectabile Morten, Belg. Hort. 16: 260. 1866. 
Zygocactus altensteinii Schumann in Martius, Fl. Bras. 4 3 225. 1890. 
Epiphyllum delicatum N. E. Brown, Gard. Chron. it. 32: 411. 1902. 
Epiphyllum delicatulum Schumann, Monatsschr, Kakteenk. 13: 9 I 903. 
Zygocactus delicatus Britton and Rose, Contr. U. S. Nat. Herb. 10: 260. 1913. 
: i inent teeth at other- 
Joints dark glossy green, about 3 cm. long, sharply serrate, with two prominent 
wise truncate Spex: Fecnuaal areole broad and thin, filled with brown wool and bristles; flowers 6 
