E. S. Luttrell

Parasitism of fungi on vascular plants

I have had one piece of advice in the preparation of the presidential address: make it short. Colleagues such as mine help keep events in perspective. I am a plant pathologist-not a mycologist who happens to be stationed in a plant pathology department, not an applied mycologist, but a professional, certifiable plant pathologist. A few mycologists are beginning to recognize that plant pathology is not applied mycology; fewer appreciate that it never was. True, the foundations for modern plant pathology were laid by de Bary in the years 1853 to 1886. In the same era Koch laid the foundations for modern medicine. Bacteriology has made important contributions to medicine, and its association with medicine has been the basis for its progress. Yet, there is no suggestion that medicine is, or ever was, applied bacteriology. If there were no viruses, no bacteria, no algae, no protozoa, no nematodes, no arthropods, no genetic abnormalities, no environmental deficiencies, no smogif all plant diseases were caused by fungi, plant pathology still would be a distinct science. Although pathologists and mycologists often range the same fields, they occupy different niches. The pathologists

Conidiogenesis and conidiomata in the Clavicipitoideae.

Microscopie optique et electronique a balayage de 2 types de conidiogenese et de la variabilite des conidiomata dans un but systematique

Ultrastructure of teliospore ontogeny in Tilletia indica

Teliospores of Tilletia indica, the Karnal bunt fungus of wheat, arose from a fixed hymenium lining all surfaces of a cavity formed by separation of the inner and outer layers of the pericarp of the grain. Scanning and transmission electron microscopy showed that the spore originated as a swelling cut off at the tip of a sporogenous hypha by a septum. The wall of the parent sporogenous cell formed the primary wall of the spore initial. Centripetal deposition of secondary wall material against the primary wall produced: 1) a thin, uniform outer layer that fused with the primary wall to form a sheath; 2) an electron opaque exospore ornamented with spines; 3) a uniform, granular endospore; and 4) a thin partition layer of sinuous lamellae separating the exospore and endospore. The complex exospore was composed of a series of concentric fibrous bands divided into two layers. In the outer ornamented layer localized deposits of dense amorphous material cemented the fibrous bands into conical spines separated by interspinal areas of loosely arranged bands. Inside of the ornamented layer the deposits of amorphous material formed a continuous dense basal layer that merged with the broad bases of the spines. The apiculus sometimes present on mature spores represented the shriveled subapical cell of the sporogenous

Development of the Conidial State of Myriogenospora Atramentosa

A liquid medium and a corn meal-malt agar medium were developed for culturing Myriogenospora atramentosa, a systemic parasite of pasture grasses. On living leaves the conidiomata that are produced in stromata precede the perithecia and are irregularly hysteriform and ephemeral. Conidia are acicular, I-celled, and hyaline. In culture, polar or lateral germ tubes from ascospore part-spores or conidia give rise to secondary conidia or develop into a mycelium. Aggregations of hyphae resembling sporodochia form in the mycelium. Simple conidiophores develop on both the sporodochia and the mycelium. The presence of an ephelidial conidial state like that in species of Balansia supports the classification of M. atramentosa in the tribe Balansiae, subfamily Clavicipitoideae, Clavicipitaceae. Light and scanning electron microscopy showed that the conidia are holoblastic on sympodial conidiophores. The occurrence of holoblastic as well as phialidic conidia indicates that conidiogenesis must be considered in the classification of the Clavicipitaceae.

Curvularia coicis and the Nodulosa group of Bipolaris.

The nodulosa group of the genus Bipolaris, including B. coicis (Nisikado) Shoemaker (= Curvularia coicis Castellani), B. kusanoi (Nisikado) Shoemaker, B. hadrotrichoides (Ell. & Ev.) Luttrell comb. nov., and B. nodulosa (Berk. & Curt. in Sacc.) Shoemaker, is characterized by ovateellipsoid to obclavate-fusoid, brown, thin-walled, 3-7-septate conidia and nodulose conidiophores with swollen, pestle-shaped tips which are at first hyaline and are late in becoming brown. Examination of the type collection of Curvularia coicis Castellani (1, 2) has shown that this species does not belong in Curvularia (5) but is probably identical with Helminthosporium coicis Nisikado (10). Since Shoemaker (12) has transferred H. coicis to Bipolaris, a reassessment of the status of the genus Bipolaris is necessary.

Ascoma morphology of Pseudopeziza trifolii forma specialis Medicaginis-sativae (Dermateaceae) on alfalfa

Ascomatal initials of Pseudopeziza trifolii f. sp. medicaginis-sativae consist of ascogonial coils forming on intracellular hyphae in parenchyma cells of living alfalfa leaflets. In some young asco...

A New Species of Eudimeriolum from Georgia

An inconspicuous pyrenomycete collected on living birch leaves in Georgia in June 1978 discharged ascospores that germinated and produced colonies on agar media. The fungus was determined to be an undescribed species of Eudimeriolumt (Dimeriaceae). In addition to being new, it is of special interest because we know of only a single previous published report (Luttrell and Barr, 1978) mentioning the laboratory culture of a dimeriaceous fungus.