TROPICAL AMERICAN ORCHIDS 
X 7. 3, petal, spread, with column and labellum X 7. 4, 
flower, side view X 6. 5, flower, torn open to show parts 
X 6.] 
Physosiphon obliquipetalus is allied to P. Cooperi Ames, 
but it has far different petals and lip. 
Costa Rica, Cartago, Santa Clara, C. H. Lankester 
680. 6500 feet altitude. (Type in Herb. Ames No. 28178.) 
Stelis Alfaroi A. & S. sp. nov. Caules secundarii con- 
spicui, monophylli. Folium oblique lanceolatum, coriaceum. 
Inflorescentiae binae, dense multiflorae. Flores parvi. Sepala 
perlate ovata, quinquenervia, lateralia obliqua. Petala cune- 
ato-obovata, apice incrassata. Labellum semi-orbiculare, 
antice truncatum. 
Plant tall and stout for the genus. Secondary stems 
conspicuous, over 15 cm. tall (incomplete below), about 3 mm. 
in diameter, monophyllous, striate-sulcate in the dried 
specimen, in anthesis with the fibres of long tubular sheaths. 
Leaf obliquely lanceolate, 15 cm. long, 3.2 cm. wide, nar¬ 
rowed to a more or less rounded apex (tip broken off), 
shortly cuneate-narrowed into a short channelled petiole 
which is about 2 cm. long, thickly coriaceous, with the mid¬ 
nerve sulcate above and bluntly carinate beneath. In¬ 
florescences (of a single flowering season) two, 16-21 cm. 
long, arising from a prominent conduplicate lanceolate 
sheath which is 2.2-2.5 cm. long. Peduncle below the 
raceme short, about 3.5 cm. long, with a single tubular bract. 
Racemes suberect to arcuate-spreading, many-flowered, very 
dense above but loose at the base, secund-flowered. Floral 
bracts hyaline, subequaling the pedicellate ovary. Flowers 
very small, spreading, glabrous. Sepals connate at the 
base for nearly half their length. Lateral sepals very broadly 
ovate, oblique; free portion 1.6 mm. long, acute, 4-5-nerved 
with the nerves carinate on the outside. Dorsal sepal similar 
but a little larger, distinctly 5-nerved with the lateral nerves 
short. Petals much smaller, cuneate-obovate, about .9 mm. 
long, apex fleshy-thickened, especially in the centre, with 
three approximate nerves. Labellum similar to the petals, 
semiorbicular, broadly truncate in front but with a slight 
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