ACCOUNT OF GENUS SEDUM AS FOUND IN CULTIVATION. 5 



which I have not seen — S. nihricaule at Washington, 5. Hemsleanum 

 at St. Louis, and S. Zentaro-Tashiroi and S. japonicum (var. 

 senanense) at Tokio. Some other species were in cultivation not 

 many years ago — for instance, S. clavifoUum, S. delicatum, S. fili- 

 ferum, S. Painteri, S. semiteres, S. suhmontanum at Washington, and 

 S. Englerianum at Dahlem, but they appear to be now lost. 



Some details as to the sources from which the species described 

 in the following pages were derived will be found on p. 19. 



In addition to species already in cultivation, some species hitherto 

 unknown in gardens were introduced, thanks to the kind offices of 

 correspondents in Asia and America ; and a few others which had 

 been lost to cultivation, such as S. pruinatum from Portugal and 

 S. lancerottense from Teneriffe, were reintroduced and distributed. 



III. Distributional. 



The genus Sedum is spread in varying abundance throughout 

 the Northern Hemisphere. The majority of the species inhabit 

 temperate countries, or, if found in lower latitudes, have their homes 

 on the mountains, so that most of them are hardy in our gardens. A 

 few species run very far north, and the genus is represented in Iceland, 

 Nova Zembla, Arctic Siberia, Alaska, and Greenland ; these northern 

 forms belong mostly to the section Rhodiola. Southward, a few 

 endemic species are found in the Philippines ; others reach the 

 Equator on the great mountains of Central Africa ; while in America 

 the genus has spread down the backbone of the continent and has 

 crossed the Equator, the most southern outpost being in Bolivia. 

 Over part of its wide range, the genus exhibits well-marked geogra- 

 phical groups, allied species being concentrated in particular areas — 

 for instance, the large Rhodiola group in Asia from the Himalayas to 

 China, the Involucrata group in the Caucasus, the rupestre group 

 in Europe ; on the other hand, the rich Sedum flora of Mexico shows 

 extraordinary variety of forms mostly without close relationship. 

 The succeeding paragraphs briefly describe the Sedum flora of the 

 main areas occupied by the genus ; on pp. 22, 23 will be found notes 

 as to the distribution of the phylogenetic groups into which the 

 genus divides itself. 



Europe. 



About sixty species of Sedum altogether occur in Europe, the 

 number increasing generally from the north-west to the south-east. 

 The great bulk of these are representatives of the section Seda Genuina 

 — mostly small creeping plants with very thick leaves, and yellow 

 or white flowers. Among them, the well-marked Rupestre group is 

 characteristically European. About one-third of the total are annual 

 plants ; these are mostly southern, and increase eastward to find 

 their maximum in the region extending from Greece to Persia. Of 

 other sections of the genus, three Telephiums occur — S. Telephium, 



