Mr. ,T. Miers on the Calyceracese. 283 



3. Boons. 



This genus was established in 1803 by Jussieu, upon a plant 

 collected by Commerson in the neighbourhood of Buenos Ayres, 

 which he named Boopis anthemoides : with this he associated the 

 Scabiosa sympag anther a of the 'Flora Peruviana/ which was 

 afterwards separated and placed in Calycera. Richard, in his 

 admirable memoir on the Calyceracece, published in 1820, gave 

 ample details of the structure of the genus, then reduced to its 

 typical species. To this original type are to be added three 

 new species recently described by Dr. Philippi, and three others 

 which I now contribute ; so that the genus will thus comprise 

 seven species. Boopis in many points approaches Acicarpha, 

 but it differs from that genus in having a gamophyllous invo- 

 lucre in the form of a depressed cup with an incised border, 

 quite free from its small globular receptacle, which is not of 

 larger diameter than its peduncular support, and which remains 

 bristled with the persistent radiating palese after the achsenia 

 have fallen off: it is also distinguished from that genus by its 

 achsenia being quite free from each other, and not accreted into a 

 cylindrical or spherical mass ; and by its calycine lobes, which 

 preserve their original form, and do not become enlarged in the 

 form of long excrescent subulate spines. It differs from Caly- 

 cera in the union of the free leaflets of the involucre into a 

 gamophyllous cup, and in its isomorphous achsenia, not hetero- 

 morphous with the calycine segments often becoming enlarged 

 into extremely long spines. 



The genus Acarpha has been proposed by Dr. Grisebach* 

 for a Magellanic plant of this family collected by Lechler. It 

 obtained this name on account of the supposed absence of palese 

 in the receptacle ; but I have examined authentic specimens of 

 Lechler's collection in the Museum of Paris, and find very 

 distinct palese present in all the capitula, though not accom- 

 panying all the florets. Even if this were a distinct genus, 

 the name would require to be changed ; but it appears to me 

 a true Boopis, as its involucrum shows; and in the peculiar 

 form of its achsenia it quite accords with B. multicaulis and 

 B. gracilis. 



Boopis, Juss. Char, reformat. — Involucrum gamophyllum, cya- 

 thiforme, depressum, submembranaceum, plurinerve, fere ad 

 medium 5-10-dentatum, dentibus integris, vel denticulatis, 

 lanceolatis, vel 3-angularibus, venoso-reticulatis, rigidulis. 

 Receptaculum parvum, convexum, paleolis linearibus, scariosis, 

 apice dilatatis, achseniis sequilongis, persistentibus echinatum. 

 Flores omnes fertiles et consimiles. Calycis tubus adnatus, 



* Diagn. PI. Philippi et Lechler, p. 37 j Walp. Ann. v. p. 142. 



19* 



