ber 1923, J. Saer 116 (U.S. Nat. Herb. 1193211); June 1939, V. 
Barnes 5923 (Herb. Ames 58216). 
ExcLUDED OR UNCERTAIN CONCEPTS 
Diacrium bidentatum (Lind/.) Hemsley in God- 
man & Salvin Biol. Centr.-Am., Bot. 8 (1888) 221. 
Hpidendrum bidentatum Lindley Gen. and Sp. Orch. 
Pl. (1831) 98. 
The type of Mpidendrum bidentatum is preserved in 
the British Museum. Study of a photograph of the type 
and diagnostic sketches in the Ames Herbarium indi- 
cates that this concept cannot be referred to Caularthron, 
but that, without a doubt, it represents, as has previ- 
ously been suggested (Williams, L. O. in Ceiba 2 (1951) 
174), Hpidendrum Boothianum dl. 
Diacrium Ulmckei Arinz/in Mitteil. Inst. Allg. 
Bot. Hamb. 6 (1927) 419. 
This concept was described on the basis of material 
which flowered in the Hamburg Botanical Garden. The 
plant had presumably been collected in Guatemala. Since 
the Hamburg Herbarium has apparently disappeared, 
we are unable to trace a type, if indeed an herbarium 
specimen were ever preserved there when the concept 
was described. After an examination of the description, 
I rather doubt that the concept can be accommodated in 
the genus Caularthron. 
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