The Taphrina Collection of A. J. Mix
Arthur Jackson Mix
(1888-1958) was on the faculty of the University of
Kansas most of his professional career, beginning in 1916.
Even today, he is considered the world authority on Taphrina,
"peach leaf curl" fungus, and his monograph is the standard reference
this group (University of Kansas Science Bulletin, vol. 33, Pt. 1, No.
1, 1949). It is suspected that Mix's graduate student,
Charles Kramer, eventually acquired his herbarium and took it with him
to Kansas State University (KSU) where he served as a faculty member.
a substantial number of Mix's Taphrina collections from KSU
transferred to NYBG, it is yet to be determined if his herbarium was
as a whole to KSU, or if some of his specimens remain at University of
The genus Taphrina,
founded by Fries in 1832 on the species Taphrina populina, is
only recognized genus in the family Taphrinaceae, order Taphrinales of
the Ascomycetes. It is a widespread genus, and at present contains
95 species, all of which are parasitic on
vascular plants. This fungus has four unique or unusual features.
(A) The assimilative mycelium is dikaryotic which immediately
it from most other ascomycetes and therefore raises the question about
the placement of this order. (B) It produces an exposed layer of asci
the surface of the host leaf. Since there is no surrounding or
fungal tissue, there is nothing that can be called an ascoma. (C) The
often bud in a rather yeast-like manner while still inside the ascus.
When the asci dehisce, they tend to split across the tip, rather than
it, so they are distinctly atypical of the operculate group.
this group sits uneasily among the other ascomycetes.
The genus Taphrina
is most often associated with peach leaf curl disease, which causes
to become thickened and distorted. Peach leaf curl disease is
is one of the most common and widespread diseases affecting peach
in the United States. As the name implies, the most common and striking
symptom of leaf curl occurs on the foliage. The fungus causes the
meristematic cells at leaf margins to proliferate quickly and randomly,
which results in the leaves becoming variously wrinkled, puckered and
In 1952-53, several
years before his death, A. J. Mix reviewed the entire collection of Taphrina
species at NYBG, and most of the specimens in the NYBG herbarium have
been annotated by him. They have been completely rearranged
according to his 1949 Monograph. His collection of Taphrina species
recently received by NY from KSC is presently being incorporated into
the NYBG Herbarium.
The following web pages contain
additional information on peach leaf curl and other diseases caused by Taphrina
State University Extension Factsheet: Peach Leaf Curl
Peach Leaf Curl and Related Diseases
(Cooperative Extension, University of Nebraska,
Institute of Agriculture and Natural Resources)
Online Guide to Plant Disease Control: Leaf Blister
(Oregon State University Department of Botany
and Plant Pathology)