16 



PRINCIPLES OF PLANT-TERATOLOGY. 



Cases of unequal dichotomy into two are more 

 frequent, as in that of Pratella campestris observed 

 Tby Heckel, where the branching occurred at the level 

 of the "ring." 



Boudier observed, like Holland, dichotomy in Phallus 

 impudicus, but in this case the branching was very 

 much deeper, and unequal, one of the arms being quite 

 vertical, the smaller one being lateral ; both occurred 

 within the same volva. His interpretation of the 

 structure was : fusion, the smaller one being carried 

 up by the larger. 



It may here be remarked that it is quite possible 

 that, in some of these cases which look like branching, 

 fusion between two stipes and fruits may be the true 

 cause of the phenomenon ; but unless unequivocal 

 evidence of fusion is present, all such cases will be 

 held to be due to forking. 



Passing from these cases in which one degree of 

 forking only obtains, we come to those abnormalities 

 whose very remarkable appearance is due to the 

 occurrence of many degrees of forking. The best 

 known instance of this is afforded by Lehtinus lepideus,* 

 and has been described by many authors, from Aldro- 

 vandi in 1671 to Buller in 1906. If grown from the 

 earliest stage onwards in the dark, two phenomena 

 occur : excessive elongation of the stipe, and multiple 

 dichotomy thereof, giving rise to a stag's-horn-like 

 structure of the whole fructification (Plate II, figs. 1 

 and 2). Correlated herewith, the pilei or caps become 

 excessively reduced in size, occurring as tiny knobs at 

 the tips of the ultimate branches, or entirely dis- 

 appearing as such, rudimentary gills being formed on 

 the sides of the branch-tips. This structure is due 

 entirely to growth in the dark ; if light be introduced, 

 pileus-formation and cessation of stipe-elongation at 

 once set in.t A similar case may also be referred to 



* Various names have been assigned to this abnormality in the past, 

 e.g. Clavaria cornuta, Ramaria ceratoides, Helvetia serpentiformis. 

 f Not a fortuitous, indefinite variation. 



