(Vou. 4 
40 ANNALS OF THE MISSOURI BOTANICAL GARDEN 
(mutations). If, аз a result of experimentation, we are forced 
to deny the existence of transitional forms as such, then that 
fact along with the fact of the existence of apparently useless 
characters suffices, according to him, to beset the selection 
theory with serious difficulties. 
Accordingly, a third possible suggestion might be offered, 
namely, to consider both varieties as elementary species, 
simultaneous mutants from H. psycodes. Since no new char- 
acters have been added, they would be what De Vries calls 
retrogressive; he even states that ‘‘there are possibly more 
species on the face of the earth at present that have arisen 
on retrogressive than on progressive lines—just as it is held 
that the monocotyledons have arisen from the dicotyledons 
by the loss of a whole series of characters.’’ 
In his paper on *Die Bedeutung sprunghafter Blütenvaria- 
tionen für die Orchideenflora Siidbrasiliens,’ Porsch tells 
how certain species of orchids brought over to Germany by 
Prof. Wettstein from southern Brazil entered on a sudden 
period of mutation, and that under his very eyes he saw the 
origin of several elementary species. He attributed the induc- 
tion of the period of mutability to the external factors of a 
changed condition of nourishment. He states that although 
he does not believe that mutation is the only way by which 
new forms may originate, yet he thoroughly believes in spon- 
taneous variability as the species-forming factor in the orchid 
family. It may not be impossible that the species H. psycodes 
is in a period of mutability; experimental studies alone could 
decide. 
In his ‘Pflanzen-Teratologie’ Penzig mentions three spur- 
less varieties of H. ciliaris, H. fimbriata, and H. hyperborea, 
respectively, as cases of peloria. Examples of pelorism 
among orchids seem to be not uncommon.  Peloria is a term 
first used by Linnaeus to describe the five-spurred flowers of 
Linaria vulgaris, newly discovered at that time. The name 
is derived from the Greek word for monster. It is now 
applied by botanists to all flowers which pass from irregu- 
larity to regularity. The lip of an orchid is really a petal 
which has become irregular in form, and in the two genera 
