120 Rydberg: Notes on Rosaceae 



Oreobatus trilohus (Seringe) Rydb. is a fourth species of the 

 genus. The variety Riibus trilohus guatemalensis Focke is of 

 little value. The characters given are not distinctive. The 

 shorter terminal lobe of the leaves is only occasional and found 

 only rarely even in specimens from Guatemala, and the color of the 

 petals, as far as I have been able to find, is always purple. 



Chiapas: Ghiesbreght, gy, 50Q. 



Oaxaca: Sierra Filipe, Pringle 4670; Liebmann; E. W. Nelson 

 1 172; 18 miles southwest of the city of Oaxaca, Nelson 141 3. 



Vera Cruz: Orizaba, Seaton 252. 



Puebla: Boca del Monte, Purpus 2453. 



Guatemala: Volcan d'Agua, Maxon & Hay 3676, 3744; 

 Pittier 32; Shannon 3631. 



RUBUS 

 Limitation of the genus and synonyms 



The only two botanists who have tried to divide Rubus into 

 several genera are Rafinesque and Greene. Some of the proposed 

 genera are habitually fairly distinct, but there are no essential 

 differentiations in the flower and fruit, on which generic lines 

 could be based. Some of the Asiatic and South American species 

 may represent distinct genera, but, as far as the North American 

 (and also European) species are concerned, there is none that in my 

 mind is different enough from the general type to make its separa- 

 tion as a genus warranted, except those removed to Dalibarda, 

 Rubacer, and Oreobatus. 



Cylactis was the first genus proposed by Rafinesque. Its type 

 was Cylactis lyncimo7itana or C. montana Raf., which is the same 

 as Rubus pubescens Raf., R. triflorus Richards, and R. americanus 

 (Pers.) Britton. This is a raspberry as far as the flowers (except 

 the filament) are concerned. The fruit approaches the rasp- 

 berries in color and flavor, but does not separate as a cap or 

 thimble. It is a dewberry as to the habit, but the receptacle 

 is not fleshy. It differs from both dewberries and raspberries 

 in the wholly unarmed plant, the broad and almost free stipules, 

 and the dilated filaments, three-toothed at the apex, the longer 

 middle tooth bearing the anther. The lack of armature (prickles 

 or bristles) is no generic character, for both Hie closely related 



