RvDBEKG : Notes on Rosaceae 401 



Schizonotus Lindl. (1830). But why should not Sericothcca Raf. 

 (1838) be considered? It was just as well |)ublished as was 

 ScJiizonotus, and was published by the same author. It is anotiier 

 illustration of how poorly digested and how incomplete Harms' 

 list is. The present writer would perhaps be willing to subscribe 

 to a list of nomina conscrvanda, provided that a good reason in 

 each case could be given ; but a list which arbitrarily retains or 

 rejects genera published under similar conditions by Hill or Adan- 

 son, as shown bv Druce in his introduction to his List of British 

 Plants, has no standing with the present writer. 



The genus Sericothcca is a very perplexing one, and it is very 

 hard to draw lines between the species. Otto Kuntze reduced 

 the whole genus to one species. Every one must admit that by so 

 doing he went too far. The genus can be divided into two types ; 

 one with the teeth of the leaves rounded or rounded-ovate, ending 

 in a short mucro, and achenes straight on the back ; the 

 other with the teeth lanceolate or triangular-ovate, ending in a 

 long mucro, and the achenes more or less curved on the back. 

 The two species would then be 5. discolor and S. argentca. This 

 would be the ultra-conservative view. Both species, especially 

 the former, would, however, show such a diversity of forms that a 

 number of varieties would have to be admitted. If S. discolor \s com- 

 pared with S. iiiicrophvlla or 5. ^;g/^^mrr/^i', few botanists would re- 

 gard them as the same species. It is only when the other 

 members of the genus are known and considered, that some would 

 regard them as varieties of one species. C. K. Schneider, who 

 can very well be credited to the conservative school, has been 

 forced to admit four species. He made the statement that he 

 could not see any difference between Holodiscus niicrophjllus and 

 H. dumosus but I think this was due to the fact that he followed 

 S. Watson in his interpretation of H. dinnosus. Watson's idea of 

 H. dumosus was an aggregate of those species which have a 

 narrow and rather simple inflorescence, /. c, Sericothcca coucolor, 

 S. niicrophylla, and .S\ glabresce?is. S. Boursicri and 5. saxicola 

 would also have been included, had they been known to Watson. 

 Now, the fact is that the original Spiraea duinosa Nutt. cannot be 

 distinguished specifically from Holodiscus australis Heller. The 

 latter Schneider admits as a good species. It is true that Spiraea 



