fusiform roots. Leaves basal, rosulate, petiolate to cuneate at 
base. Scape erect, vaginate, terminated by a many-flowered, 
more or less spirally twisted spike. Flowers small, inconspicuous. 
LECTOTYPE: Spiranthes esmeralda Linden & Rchb.f. [Cor- 
rea in Darwiniana 11:68, 1955] 
Seven species native to tropical and subtropical America, 
ranging from Guatemala to Brazil. 
Index to species 
angustisegmenta Garay 
Mesadenella atroviridis (Barb.Rodr.) Garay, comb. nov. 
Basionym: Cyclopogon atroviridis Barb. Rodr., Gen. et Sp. Orch, Nov. 
2: 284, 1881. 
cuspidata (Lindl.) Garay 
esmeralda (Linden & Rchbhf.) Pabst & Garay = Mesadenella cuspidata 
(Lindl.) Garay 
Mesadenella margaritifera (Linden & Rchb.f.) Garay, comb. nov. 
Basionym: Spiranthes margaritifera Linden & Rchb.f. in Gard. Chron. 
219, 1866. 
peruviana Garay 
Mesadenella petenensis (L.O. Wms.) Garay, comb. nov. 
Basionym: Spirantheses petenensis L.O. Wms. in Phytologia 25: 460, 1973. 
Tonduzii (Schltr.) Pabst & Garay 
Mesadenus Schltr. in Beih. Bot. Centralb. 37 (2): 367, 1920. 
Etymology: Mesos = middle and aden = gland, describing 
the manner how the pollinia are attached to the 
rostellum. 
Sepals more or less similar, subparallel, somewhat diverging 
towards the arcuately spreading apices, often insignificantly 
connate basally; dorsal sepal slightly concave and adnate to a 
short distance to back of column; lateral sepals with an oblique 
base, adnate to column-foot. Petals agglutinate with dorsal 
sepal, more or less falcate with a decurrent base. Lip condupli- 
cate to navicular, subsessile with thickened, auriculate base, 
arcuately recurved in front. Column arcuate, dorsally united 
with median sepal, basally produced in a decurrent foot; stig- 
mata 2. confluent, sometimes obscurely 2-lobed at apex; rostel- 
lum very narrow, emarginate with a small, sometimes rather 
obscure. dorsal toothlette in middle. Anther bivalvate, rather 
335 
