THALLUS 250-385 µm long, olive-brownish; perithecia and frequently appendages, except for the basal cells, darker.
RECEPTACLE 170-300 µm long, usually forming an elongate stalk, composed of five receptacle stalk cells (rscI-V) and two stalk cells of perithecium (scpVI and VII); cell I usually bent, up to two times longer than broad, but shorter than cell II, with a dark-coloured foot (f); cell III slightly elongated; cell IV triangular; cell V obtriangular. Insertion cell lacking. Cell V proliferates upwards into a series of 4-8 cells gradually decreasing in size; each cell bears a small cell from which a double row of secondary appendages (sapp), up to 500 µm long, composed of elongate cells, laterally arise. The basal cell of each appendage (bcapp) is large, somewhat inflated, and continuous with two, usually simple, rarely once-branched, straight, long sterile branchlets; it also frequently produces a short antheridial branchlet consisting of a small stalk cell and two adjacent antheridia; basal cell of the appendage (and the suprabasal one when the branch is twice-ramified) has dark septa on both ends; between cell IV and the lowest derivatives of cell V, an additional small cell is present.
PERITHECIUM (p) 110-150 x 40-75 µm, ovate or elongate, 3/4 free, slightly asymmetrical, with subapical blackish suffusion and posterior, more prominent, rounded lips.
SPORES (s) hyaline, 55-65 x 6-8 µm.
HOST AND DISTRIBUTION. The specimens of L. fasciculata presented here are from Patrobus atrorufus (Strøm) (Carabidae). The hosts of the fungus also are other species of the genus Patrobus, as well as those of the genus Chloenius and some other genera of the family Carabidae (Majewski 1994).
Laboulbenia fasciculata has been found to occur in Asia, the whole Europe, Africa, as well as in South and North America (Majewski 1994).
NOTES. Of the two forms of the species described, L. fasciculata and L. fasciculata f. omophroni Speg., only the former has been found in Poland (Majewski 1994).
Majewski T. 1994. The Laboulbeniales of Poland. Polish Bot. Stud. 7, 3-466.