134 TRANSACTIONS OF THE 
It is expected that the sporidia from the teliospores 
will inoculate one and only one, or at most two or three 
very nearly related, species of host-plants. Imagine the 
surprise of the botanical world when the peculiar case of 
Puccinia subnitens Dietel was recognized. It has been 
proved by inoculation experiments that its sporidia produce 
aecia on Cleome serrulata, Cleome spinosa, Chenopodium 
album, Radicula sinuata, Sisymbrium incisa, Salsola Tragus, 
Lepidium apetalum, Lepidium virginicum, Capsella Bursa- 
pastoris, Erysimum asperum, Atriplex hastata and Sarco- 
batus vermiculatus—twelve species representing three very 
distinct families of plants. 
Another rust of much interest, Aecidium tuberculatum, 
E. & K., occurring on Callirrhoe involucrata, has been con- 
sidered of much interest because its mycelium seems to be 
perennial. Now, an aecium is at most only a temporary 
structure, and it has no business with a perennial mycelium! 
On this account, the rust was discussed at some length in 
1904 by Mark A. Carleton in Bulletin 63 of the Bureau of 
Plant Industry. But the apparent discrepancy has just 
been explained by Dr. J. C. Arthur and F. D. Fromme. In 
the February, 1915, number of the Bulletin of the Torrey 
Botanical Club, it is shown that the rust is really an Endo- 
phyllum in the telial stage (instead of the aecial stage of 
some rust of the genus Puccinia or Uromyces). The genus 
Endophyllum is one in which the telial form resembles very 
closely in appearanc the aecial stage of other rusts. Arthur 
and Fromme succeeded however in producing the conclusive 
promycelia and sporidia by means of the Kunkel method of 
sowing the spores on the surface of a non-nutrient agar. 
It is the rule among heteroecious rusts having all spore 
forms that the teliospores will not germinate until the fol- 
lowing spring; i. e., not until they have been exposed to the 
rigors of winter. But Uromyces Houstonianus (Schw.) 
Shelton is the single known exception to this rule by ger- 
minating as soon as produced. It occurs on Sisyrinchium 
graminoides Bicknell. 
Some of the most striking departures from rule are 
found in the genus Gymnosporangium. These rusts are 
