i66 
BASCOMBE BRITT HIGGINS 
regularly stellate manner, hymenium grayish to creamy white; asci clavate 70-80 X 
14-19/1, opening by a pore in the papillate apex; spores elongated, fascicled in end of 
ascus, 40-51 X 3. 5-4. 5m, continuous or occasionally once or twice septate; para- 
physes usually simple though occasionally branched, slightly enlarged at tip, about 
as long as asci; apothecial conidia very long, 58-87 X 3.5-5M, once-septate with 
usually a single vacuole in each cell. 
Conidial stage (Cylindrosporium lutescens) : spots small, brown to reddish brown, 
in early summer dropping out from leaves of some species and producing rounded 
"shot holes"; mycelium intercellular, with haustoria which penetrate the host cells; 
acervuli subepidermal, amphigenous; conidia exuding in masses or in long tendrils 
from the break in the host epidermis, long, slender 50-87 X 3.5-5M, continuous or 
1-3 septate, microconidia (spermatia?) produced in the same acervuli in late summer, 
Small, continuous, 4-5 X im- 
Conidial stage parasitic in leaves of P. serotina and in leaves and fruits of P. 
virginiana, and P. mahaleb. Ascigerous stage saprophytic on fallen leaves of the 
same species in May and June following the conidial stage of the previous summer. 
Latin diagnosis: Ascomatibus hypophyllis, sparsis, subepidermicis, erum- 
pentibus, disciformibus, 130-300 X 70-1 50^, luteis vel ferrugineis, primum clausis 
deinde in lacinias plures acutas dehiscentibus; disco pallido carneo vel griseo; ascis 
clavatis, crassiuscule stipitatis, 70-80 X 1 4-1 9m, octosporis, apice papillato; para- 
physibus, filiformibus, simplicibus aut ramosis; sporidiis fasciculatis, linearibus, 
35~50 X 3-5-4-5M, simplicibus aut 1-3 septatis; conidiis in apotheciis filiformibus, 
flexuosis, 50-80 X 2.5-4M, i-septatis. 
Hab. in dejectis foliis Pruni serotinae, P. virginianae et P. mahalebis. 
Status conidicus; maculis sparsis vel confluentibus minutis brunneis aut rufis- 
brunneis, interdum majusculis dejectis; acervulis solitariis, amphigenis, subepider- 
micis, disciformibus; conidiis, fihformibus, flexuosis, denique emergenti-super- 
ficialibus, hyalinis, continuis 50-87 X 3.4-5M, i septatis; conidiis minoribus autumno 
hyalinis, continuis 4-5 X 1.5. 
Hab. in foliis vivis Prunii serotinae, P. virginianae, et P. mahalebis. 
General Discussion 
There are many points of interest in the life history and develop- 
ment of the CyUndrosporium on stone fruits, not the least of which is 
their relation to the host tissue. The parasitic stages of Ascomycetes, 
other than the Perisporiales which have epiphytic mycelium, usually 
kill the host tissue outright. In two notable exceptions to this, 
Gnomonia erythrostoma Pers., and Polystigma ruhrum .(Pers.) D. C. 
no haustoria have been found. Haustoria have been described for a 
large number of the Perisporiales (in the Erysiphaceae by many 
workers and by Maire (18) for Meliola^ and Asterina). In one of the 
Erysiphaceae, Oidiopsis taurica Salmon, the mycelium is endophytic, 
and it is partly so in Phyllactinia corylea (see Palla (21) Smith (25) 
8 Meliola is placed in the Perisporiales by Saccardo. 
