ADDITIONAL RECORDS: From organic debris under moss, collected on trail to Wombat Lake, New Zealand, February 1989; from leaf mould, collected on trail to Wombat Lake, New Zealand, February 1989; from organic debris, collected under liverworts, trail to Wombat lake, New Zealand, February 1989; from soil collected beside path, Queenstown Park, New Zealand, February 1989; from soil, collected on the Totara Walk, Pelorus Bridge Park, New Zealand, February 1989; from organic debris collected at park headquarters, Waitakere Range, New Zealand, March 1989.

Conidia of H. appendiculata were added to fresh cultures of bdelloid rotifers, and these were harvested and examined at intervals. After 18 h a sample of rotifers was mounted in water and examined under the microscope. Spores were observed lodged in the mastax. The first evidence was the presence of one or several clear circular areas on the surface of the mastax. Clear areas were always found in association with a lodged conidium (Figs. 8-10); in some cases the orientation of the conidium was established and the clear zone corresponded with the basal appendage that had become attached or lodged in the mastax (Fig. 9). As many as five circular areas were observed in the same host. From each lodged conidium, a slender clavate germ tube developed (Fig. 10). In 36 h a branching system of turbinate, assimilative hyphae had developed that filled the body cavity of the rotifer. Reproductive hyphae then broke out through the cuticle of the host to the aqueous exterior. Short conidiophores developed directly from the surface of the host that produced phialides singly or in lateral or apical verticils (Figs. 3, 4, 7).
Conidiophores are simple and hyaline and consist of one or a few cells; they are up to 30(50) µm long and 1.7-2.2 µm wide. The phialides are ampulliform and narrower at the base, somewhat swollen towards the apex, and narrow abruptly to form a short, often sharply reflexed tip. A shallow, membranous collarette is found on older phialides. The phialides are borne laterally and singly or in terminal clusters mostly of three. In terminal clusters, the central phialide is often markedly longer than the two lateral phialides (Fig. 4). The conidia are hyaline, nonseptate, and T-shaped to Y-shaped in face view (Figs. 1, 12). In side view, they are curved sharply at the base and to a lesser extent at the apex to give the conidium a bent appearance (Fig. 11). In face view, the reflexed portion at the base appears to be a circular, disc-shaped structure with a central depression (Fig. 1). It is easier to observe the basal apendage of H. appendiculata than H. tribrachispora, as the conidia are much larger. Conidia are 5.5-6.5 µm tall and 5.0-7.0 µm at their widest point across the arms of the T. Conidia gather in balls at the mouth of the phialide if undisturbed. In an aqueous medium, however, with active rotifers or other motile animals, the conidia are readily dislodged, and only one or two conidia remain attached to the conidiogenous cell. Observations on early stages in the development of the conidium indicated that the basal attachment is the first part of the conidium to be formed (Fig. 5).

HABITAT: Parasitic in bdelloid rotifers.

Hyphae bibulae ramosae cum cellis clavatis usque ad turbinatis; conidiophora brevia, hyalina, simplicia vel ramosa aliquando, usque ad 30 (45) µm longa x 1.7-2.2 µm lata; phialides ampulliformes vel longae et cylindricae, hyalinae, cum minuto collare membranaceo, singulatim vel gregatim, (5.5)7.5-12 µm longae x 2.0-3.0 µm latae; phialoconidia hyalina, nonseptata e conspectu frontis T-forma usque ad Y-forma, e conspectu lateris curva clare cum orbiculata appendice basilare, 5.5-6.5 µm longa x 5.0-7.0 µm lata, colligentia in globis juxta apicem phialidis.

Development of the conidiophores and conidiogenous cells was somewhat variable. When first observed in the original rotifer cultures, supplemented with soil or debris, the conidiophores and conidiogenous cells were short and stubby. Later, however, when conidia from pure cultures of the fungus were added to cultures of bdelloid rotifers and bacteria, the conidiophores and phialides were sometimes short with reflexed tips and at other times elongate with straight tips (Figs. 2, 6). The reason for this variability was not established but may have been related to the levels of bacteria in the rotifer cultures. In either case the conidia were identical. Observations on cultures several weeks old failed to reveal the presence of any resting spores associated with this fungus.

TYPE: Slides in herbarium (OAC10854), isolated from soil collected in sheep pen near Kuriwara Stream, New Zealand, 19 December 1988.