For the gardener’s convenience we are classifying the more im- 
portant varieties according to their susceptibility to mosaic: 
Group 1 
The first group consists of a number of fine standard garden 
lilies which always have mosaic. One or two have had it for hundreds 
of years. In spite of this they are all splendid plants that delight 
their owners year after year. 
L. candidum L. chalcedonicum (with rare exceptions) 
L. elegans L. princeps, George C. Creelman 
L. testaceum L. T. A. Havemeyer 
L. umbellatum L. tigrinum (with rare exceptions) 
(old forms) 
Group II 
The second group, at the other extreme as to susceptibility, con- 
sists of those lilies that resist infection to the point where they can be 
safely considered immune. 
L. Brownii (type) L. Martagon (all forms) 
L. giganteum L. pardalinum (all forms) | 
L. Hansonii The Martagon-Hansonii hybrids 
Group III 
The third group is liable to infection but does not acquire it read- 
ily and tends to survive for a number of years in the garden, though 
the plants will gradually deteriorate somewhat and may finally die 
out.1 
L. regale L. Maxwill! 
L. tenuifolium L. sulphureum! 
L. Willmottiae! L. monadelphum! 
L. Henryi! L. Szovitsianum! 
L. cernuum All of the Preston, Stooke’s and 
Bellingham hybrids! 
Group IV 
The fourth group consists of those lilies that are most highly sus- 
ceptible to infection and rarely survive more than a single season when 
infected. 
L. auratum L. japonicum 
L. canadensel L. superbum} 
L. formosanum 
These classifications while an invaluable guide to the gardener are 
somewhat artificial. Actually the two hundred odd varieties and species 
of lilies run the whole gamut from susceptibility to immunity and 
within each classification there is considerable range in regard to 
immunity. This is particularly true of Group IV in which L. auratum, 
L. formosanum, and L. japonicum are the most highly susceptible that 
we know, while L. canadense and L. superbum can stand a fairish 
amount of exposure. Now and then we find individual clones that 
show a real degree of desistance. 
Mosaic is spread from one plant to another ONLY by means of a 
small group of sucking and chewing insects. It does not travel through 
the air or soil. Aphis are the principal culprits. The farther north one 
1 Those designated are less susceptible than the others within the giv- 
en group. Also, individual plants within Groups HI and IV may 
prove relatively resistant. 
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