ACCOUNT OF GENUS SEDUM AS FOUND IN CULTIVATION. 13 



V. Variation. 



The species of the genus Sedum present a wide range of size, form, 

 and colour. Minute creeping species are found in both the Old and 

 New Worlds, and many of the annual species are very small ; on the 

 other hand, some of the herbaceous perennials of the Telephium 

 section produce annually stems a yard or more in height, and a few 

 of the sub-shrubby Mexican species are equally tall. As regards 

 duration, about four-fifths of the known species are perennials — 

 many herbaceous (that is, dying back to the root in autumn), many 

 evergreen, a few deciduous (that is, having perennial stems but losing 

 their leaves in winter) ; the remaining species are mainly annuals, 

 a few being biennials. 



Hairiness is rare in the genus ; and the most constant characteristic 

 is a tendency to succulence, which in many species attains a very 

 marked development, and enables them to Uve in very dry places. 

 As an example of the amount of water which these plants may contain, 

 a leaf of 5. nutans, a Mexican species bearing the largest leaves found 

 in the genus, weighed 75 ounce fresh, and when thoroughly air-dried 

 •02 ounce — in other words, f|, or over. 97 per cent., of its weight was 

 due to water stored up in the leaf. 



The species of Sedum differ much as regards the variability which 

 they display. Some are very stable and constant in character ; many 

 others vary within limits, mostly as regards habit and leaf ; while 

 some are highly variable, and, as regards at least general appearance, 

 differ more from their type than some allied but quite distinct species 

 do from each other. Thus, S. roseum, at once the most variable and 

 the most widely distributed of Sedums, has flowers which range from 

 the normal yellow through red to deep purple, and which may be 

 dioecious or hermaphrodite ; the stem may be stout or slender, a 

 couple of inches or a foot in height ; the leaves green to very glaucous, 

 broadly ovate to linear, entire to deeply toothed. Other conspicuously 

 variable species are S. album, altissimum, anopetalum, reflexum, Aizoon, 

 spurium, Telephium. 



Appended are notes of the more conspicuous cases of variation 

 (including " sports ") found among the cultivated Sedums : 



Roots varied and often characteristic — thick and tuberous (section 

 Telephium especially), woody and hard (section Aizoon), or fibrous. 



Root-stock thick and elongate with conspicuous scale-leaves (many 

 Rhodiolas), or spreading laterally into a fleshy mass (other Rhodiolas, 

 Sedastrum), or absent. 



Stem very variable as regards form and duration ; perennial and 

 semi- woody (e.g. S. populifoUum and many Mexican species), creep- 

 ing and branching indefinitely (Seda Genuina), annual and erect 

 (Telephium, Aizoon, &c.). 



Leaves mostly entire, sometimes serrate, never more divided 

 than pinnatifid (S. trifidum) ; spherical or cylindrical to flat, but 

 never really thin ; green or glaucous, rarely hairy or glandular ; sessile 

 or stalked, often spurred at base. 



