Blake — New and Noteworthy Compositae 27 
exserti obtusi non appendiculati in dorso hispidulo-puberuli. — 
Coaunulta: rocky slopes, Sierra de Parras, Mar. 1905, Purpus 1005 
(rypPE in Gray Herb.). — Distributed as Aplopappus laricifolius 
var., but that species has small more or less turbinate heads and 
different involucre. In shape of heads E. parrasana is more nearly 
related to E. pinifolia (Gray) Hall, but it is very distinct from 
that species and from E. Nelsonii (Fernald) Blake in involucral 
characters. 
ERIGERON (Caenotus) BONARIENSIS L. This wide-ranging weed 
has by nearly all authors been maintained as distinct from 2. 
linifolius Willd. As shown by abundant material in the Gray 
Herbarium, the introduced plant of the Old World and of the 
south-eastern United States has almost always been distributed 
as EFrigeron linifolius or as Conyza ambigua DC., one of its accepted 
synonyms, while the plant of Mexico and Central and South 
America has quite as regularly been called £. bonariensis L. The 
origin of this treatment is doubtless to be sought in the habitats 
attributed to the two supposed species by their describers, E. 
bonariensis L. having been based on a plate of Dillenius (Hort. 
Elth. 344, t. 257) representing a plant grown from seed from 
Buenos Ayres, while E. linifolius Willd. was described as a garden 
weed of Europe of unknown nativity, and its synonym, Conyza 
ambigua DC., from artificial prairies about Nismes and Mont- 
pellier, growing with E. canadensis. Prolonged study of the large 
series representing both names in the Gray Herbarium has failed to 
show any conclusive differential characters. Neither in color’ of 
pappus, pubescence of stems, leaves, or involucre, shape or cutting 
of leaves, nor in number of florets can any concomitant characters 
be found. The number of hermaphrodite flowers in heads of E. 
‘bonariensis chosen at random varies from 7-18, that of the female 
florets from 90-280; in specimens typical of E. linifolius the same’ 
numbers run from 8-9 and 124-180 respectively. The shape of 
the leaves is extremely variable, but a specimen from Buenos 
Ayres, type locality of E. bonariensis, collected by Bacle and typify- 
ing the E. bonariensis of the Prodromus, is absolutely indistinguish- 
able in foliar or other characters from E. linifolius. 
Although there can be little doubt of the identity of 2. bona- 
riensis and E. linifolius when careful comparison is made of a full 
series of the two supposed species, there are certain variations 
