1918] JACKSON—PUCCINIA 301 
Schw. No other rust with which this could possibly be confused is known to 
occur on the stems of Ambrosia or Chenopodium, or on any other host within 
the range of this species. 
LAGERHEIM based his P. Jongipes on material of P. bullata Schw. in the 
E. Fries herbarium, communicated by ScHWEINITZ, said to be on culms or 
petioles of Ambrosia sp. 
Dietet (/.c.) based his varieties on supposed differences in the length of 
the pedicel in this rust on different hosts, a difference which is not borne 
out by an examination of the large series of specimens in the Arthur 
herbarium. 
That the rust on the stems is the same as the more common, or at least 
more frequently collected, form on the leaves has been shown by ARTHUR, 
who, in 1916 (Mycol. 9:302, 1917), using telial material from the stems of 
Vernonia sp. collected by C. H. CRABILL at Cliffview, Va., and communicated 
F. D. Fromme, succeeded in obtaining the development of pycnia and 
uredinia on the leaves of Vernonia sp. This culture also demonstrates that 
this rust, whose life history has long been in doubt, is a brachy-form referable 
to the genus Bullaria. Pycnia have not been observed in any field collections 
thus far studied. 
14. Puccinta Lorentzit P. Henn. Hedwigia 35:239. 1896. 
The type of this species was collected by Lorentz in Argentina, February 
1878, on Vernonia Lorentzii Hieron. It is also recorded from the same region 
on V. mollissima and from Brazil on V. scorpioides. The only specimen 
recorded by HENNiNGs, which has been seen by the writer, is presumably the 
collection which he records as on Vernonia sp. made by £. Ule (1414) in 
Sta. Cathrina pr. Tubarao, Brazil. The specimen examined is from the 
herbarium of E. W. D. Horway and agrees with the data given by HENNINGS, 
except that the host is V. scorpioides and the number 1441. This specimen 
bears uredinia only, and the spores, as stated by HENNINGS, differ slightly from 
those of the other collections. The spores are ellipsoid to obovoid, 23-24 by 
26-32 w, wall cinnamon brown, 1.s-2 thick, minutely and moderately 
echinulate, the pores 3, equatorial. Another specimen distributed by VESTER- 
GREN (Micromycetes rariores selecti 1289), collected by Rob. E. Fries in 
Prov. Jujuy, Argentina, on V. scorpioides, has been examined and found to 
bear uredinia only, the spores being similar to the Ule collection. In the 
absence of other material for examination it is possible that the assignment in 
the preceding key is incorrect. 
15. Puccrinia semimnscutpra Arth. Bot. GAZ. 40:204. 1905. 
O. Spermogonia epiphyllous, few in small groups, punctiform, 
honey yellow becoming brown, immersed, subepidermal, globose, 
150-180 pw across. 
