PLANT NOTES FOR 1913, ETC. 



313 



[* As a hybrid of perforatum and quadrangulum the commutatum 

 Nolte was held to be. Also Rouy and Foucaud interpret H. com- 

 mutatum as a hybrid, but they neglect to name the parent species. 

 This plant is distinguished from our Desetangsii by the blunt calyx 

 tip (//. mixtum also by having only two ridges on the stem). From 

 the description and figure of Reichenbach it appears to belong to one 

 of the closely related forms of maculatum ] 



Not much probability supports the opinion of those authors who 

 would bring Desetangsii (either as variety, hybrid, or intermediate 

 form) into relation with acutum, for of the distinguishing characters 

 of this last species (form and delicate dotting of the leaves, small pale 

 flowers) there is in Desetangsii no trace to be discovered. Against its 

 intermediate position between acutum and maculatum is further 

 opposed the size of the flowers, as well as the circumstance that as a 

 matter of fact a hybrid is known, acutum x maculatum, which is 

 clearly different from Desetangsii, and against one between acutum 

 and perforatum is the form of the calyx tip, which is broader than in 

 both the named species (in favour of acutum x perforatum the 

 circumstance may well carry weight that Desetangsii, at least in 

 France and in Switzerland, occurs almost without exception together 

 with these species). There is consequently, if one will not from the 

 beginning allow to Desetangsii a systematic independent rank, chiefly 

 the consideration of the intermediate position between maculatum and 

 perforatum, and indeed in the newest monograph of the group A. 

 Frolich regards Desetangsii as a direct hybrid of these two species. 

 Now, if no serious impediment stands in the way of this view, the 

 occurrence of Desetangsii demands consideration with respect to its 

 hybrid nature. Our plant inhabits by preference in Switzerland and 

 in France the plains and the lower mountain regions, whilst the 

 centre of distribution of H. maculatum lies in the subalpine and 

 alpine region, so that Desetangsii and maculatum, in their distribution 

 for the most part exclude each other. [//. maculatum prefers moors, 

 open woods, and alpine pastures, and also relatively dry places, 

 whereas Desetangsii on the contrary loves marshy meadows.] On the 

 other hand the most recent investigations of A. Frolich, who, in the 

 neighbourhood of Graz, met with Desetangsii abundantly in company 

 with maculatum and perforatum, and was often able to trace a 

 perfectly graduated row of forms from one species to the other, have 

 shown that Desetangsii may under the circumstances be a hybrid. 



