552 PROCEEDINGS OF THE ACADEMY OF [1895. 



nothing new was contributed until within the last decade. It was, 

 indeed, as recently as the year 18HM that, in a peculiar district of 

 the Califbrnian territory, I discovered a very clear, new species, 

 presenting fruit characters so precisely conformed to those of some 

 capparids, that I at once published the species as T. capparideum ; 

 and still more recently a third species has been detected by Dr. 

 A. Davidson, in southern California, aud published by him under 

 the uncomplimentary name of T. dubium. 



On my return from Europe a year ago, having seen and carefully 

 examined not only Hooker's type specimens, but also other valuable 

 and instructive materials at Kew, I was ready to give, and had 

 hoped to have written before this, what is still much needed, a 

 critical revision of the species. 



This generic type is altogether Californian, none of the species 

 ranging eastward beyond the western foothills of the Sierra Nevada, 

 or extending northward beyond the valley of the upper Sacra- 

 mento ; though to the southward one has been found as far beyond 

 the State boundary as San Quentin on the peninsula of Lower 

 California. 



From almost all known cruciferous plants, and from all other 

 American crucifera?, these differ notably, and very constantly, in 

 their leafy, or at least leafy-bracted inflorescence ; a character 

 which they have in common with all capparids; and, if the re- 

 markable T. capparideum, with its ample bladdery and wholly par- 

 titionless pod, dehiscing from the apex rather than from the base, 

 had been the type of the genus, one might say that the seeds alone 

 favor the retention of it within the order of Cruciferse, all other 

 less essential characters being those of the Capparidia?. 



By some error, either of Mr. Bentham's pen or of the printer, 

 the number of species of Tropidocarpum is given, in the Genera 

 Plantarum, as six, instead of one, or at most two; for at the time 

 that work was published only the two original Hookerian species 

 had been published, and even of these, one was beginning to be 

 looked upon as of questionable validity. 



Although the plants vary considerably in mode of growth, pu- 

 bescence, etc. , the pods are of such diversity as to render it impos- 

 sible that any botanist should treat the species as one only; and, 

 if not one, simply, no less than four must, in all consistency, be 

 recognized. These may be characterized essentially as follows : — 



