Refugium Botanicum.] [ October, 1872. 
TAB. 105. 
Tribe VANDER. 
Genus OrnitTHrIpIum, Salisb. 
O. pensum, [chb. f.; Seemann, Bonplandia, ui. 217. Caulescens, 
caule rectiusculo dense vaginato, vaginis demum cinnamomeis, 
pseudobulbis oblongis seu ligulatis ancipitibus monophyllis, 
nunc valde distantibus nune approximatis, antiquioribus sem- 
per lateralibus, folio cuneato oblongo-ligulato seu ligulato, apice 
obtusato emarginato, floribus in axillis vaginarum fasciculatis, 
pedunculis tenuissimis, vaginis quibusdam arcte acutis pale- 
aceis, bractea paleacea cupulata apice ampliata seu arcta, 
ovarium pedicellatum non equante, sepalo dorsali ligulato 
acuto fornicato, sepalis lateralibus oblongo-ligulatis acutis sub- 
longioribus, labello suppositis, tepalis ligulatis acutis brevior1- 
bus, labello ungue immobili columne affixo trifido, laciniis 
triangulis parvis basilaribus erectis, lacinia lgulata acuta 
mediana, callo transverso semilunato inter lacinias laterales, 
fovea nectarifera postposita, columna clavata, juxta foveam 
seepius excisa, rostello subproducto, anthera mitrata, polliniis 
sphericis seu subsphericis postice fissis per paria incumbenti- 
bus, caudicula ligulato-lineari, glandula ovali.— Mavillaria 
densa, Lindl. B. Reg. xxi. 1886, tab. 1804. 
This species appears to be exclusively Mexican. I have at 
hand wild specimens from 8. Pedro Nolasco, Jiirgensen, 895! 
Mirador on oaks, Galeotti, 5121! Liebmann, 1842, 1843! Heller! 
Misantla in arboribus, Schiede! Zacuapan, Leibold! Ehrenberg! 
The glomerate copious flowers are greenish whitish, with some 
purple around the anther, and a white lip, with a purplish disk. 
Stem erect, with many sheaths, finally turning brown. Pseudo- 
bulbs oblong or ligulate, ancipitous, one-leaved, now very distant 
from the developed length of the internodes, now approximate, the 
older ones always lateral. Leaves single, the only developed ones 
on the pseudobulbs oblong-ligulate or ligulate, blint or emar- 
ginate at their apex. Flowers in the axils of the sheaths, fasci- 
culate. SF lower-stalks very slender, with some narrow acute 
paleaceous sheaths. Bract paleaceous, broadened at the apex, or 
narrow, not reaching the length of the stalked ovary. Dorsal 
sepal ligulate-acute, fornicate. Lateral sepals oblong-ligulate, 
