ACAULOPAGE Drechsler, 1935 (Mycologia 27:185), 27 species (Drechsler, 1935).

Haustorial parasites of amoebae. Hyphae coenocytic, with few branches, capturing amoebae with yellowish adhesive, producing branched haustoria in the host. Merosporangia unispored, with 0-many appendages, variously shaped. Zygospores more or less globose, wall ornamented with a dimpled or warted wall; suspensors hyphoid

Type species: A. rhaphidospora

A. acanthospora Drechsler, 1938 (Mycologia 30:151) (Drechsler, 1938).
A. acanthospora var. magna Juniper, 1953 (Transactions of the British Mycological Society 36:356) (Juniper, 1953).
A. aristata Jones, 1959 (Transactions of the British Mycological Society 42:76) (Jones, 1959).
A. baculispora Drechsler, 1948 (Mycologia 40:93) (Drechsler, 1948 ; Duddington, 1951).
A. bicornis Drechsler, 1955 (Mycologia 47:369) (Drechsler, 1955).
A. ceratospora Drechsler, 1935 (Mycologia 27:194) (Drechsler, 1935).
A. cercospora Drechsler, 1936 (Mycologia 28:372) (Drechsler, 1936).
A. crobylospora Drechsler, 1947 (Mycologia 39:275) (Drechsler, 1947).
A. dactylophora Drechsler, 1955 (Mycologia 47:367) (Drechsler, 1955).
A. dasyspora Drechsler, 1955 (Mycologia 47:365) (Drechsler, 1955).
A. dichotoma Drechsler, 1945 (Mycologia 37:19) (Drechsler, 1945; Jones, 1959).
A. gomphoclada Drechsler, 1942 (Mycologia 34:281) (Drechsler, 1942).
A. gyrinoides Drechsler, 1948 (Mycologia 40:98) (Drechsler, 1948).
A. hystricospora Drechsler, 1946 (Mycologia 38:138) (Drechsler, 1946).
A. ischnospora Drechsler, 1947 (Mycologia 39:268) (Drechsler, 1947; Duddington, 1951; Jones, 1959).
A. ischnospora var. pleacra Drechsler, 1959 (Mycologia 51:806) (Drechsler, 1959).
A. lasiospora Drechsler, 1942 (Mycologia 34:276) (Drechsler, 1942).
A. longicornis Drechsler, 1955 (Mycologia 47:371) (Drechsler, 1955).
A. lophospora Drechsler, 1946 (Mycologia 38:136) (Drechsler, 1946, 1951; Jones, 1959).
A. macrospora Drechsler, 1935 (Mycologia 27:190) (Drechsler, 1935).
A. marantica Drechsler, 1939 (Mycologia 31:148) (Drechsler, 1939).
A. pectospora Drechsler, 1962 (American Journal of Botany 49:1089) (Drechsler, 1962—transferred to Zoophagus).
A. retusa Jones, 1959 (Transactions of the British Mycological Society 42:79) (Jones, 1959).
A. rhaphidospora Drechsler, 1935 (Mycologia 27:188) (Drechsler, 1935).
A. rhicnospora Drechsler, 1935 (Mycologia 27:192) (Drechsler, 1935; Jones, 1962).
A. stenospora Drechsler, 1941 (Mycologia 33:257) (Drechsler, 1941; Juniper, 1953).
A. tenuicornis Drechsler, 1959 (Mycologia 51:802) (Drechsler, 1959).
A. tetraceros Drechsler, 1935 (Mycologia 27:196) (Drechsler, 1935, 1942; Duddington, 1951; Park, 1971; Jones, 1959).
A. tetraceros var. longa Jones & Peach, 1959 (Transactions of the British Mycological Society 42:95) (Jones, 1959; Jones and Peach, 1959).
A. tigrina C. Ciccicone, 1989 (Micologia Italiana 18:29) (Ciccarone, 1989).
A. trachyspora Drechsler, 1959 (Mycologia 51:811) (Drechsler, 1959).

Twenty-seven species have been described in Acaulopage; they are all parasites of amoebae. The fertile hyphae grow along the surface of the substrate and the merosporangia are more or less erect when formed. Merosporangia can be allanoid, ellipsoid, obovoid to irregular in shape. Each merosporangium most commonly has one or more appendages but an appendage may not be present. Each appendage can be simple or branched.

Drechsler (1935) was able to recognize Acaulopage rhaphidospora because the merosporangia, which are produced aerially, are borne perpendicular to the substrate surface. The propagules are often produced close to the inoculum and are difficult to observe because the apex only is visible. Slides can be made for observation using the oil immersion lens of a compound microscope by removing the top layer of the agar with a moist razor blade, transferring it to a slide, and covering the specimen with a no. 1 coverslip. Drechsler notes that the fungal hyphae may smaller than the width of many bacteria, the amoebae host and haustoria may be visible; zygospores may be formed aerially and subaerially and also should be observed if they have been produced. Acaulopage macrospora (Drechsler, 1935) produced more merosporangia but it was found in only a single Petri dish. Appendages of Acaulopage rhicnospora appear collapsed and shrivaled while still aerial but after being observed in water mounts they are difficult to observe using the oil immersion lens on a compound microscope. The most common of the amoeba parasites described by Drechsler in 1935 is A. ceratospora. The appendages of A. tetraceros probably keep the spore floating on a wet surface (Drechsler, 1935).

Another species that was found in a single Petri dish is A. marantica (Drechsler, 1939). The merosporangia is long-fusiform with a single apical appendage. Zygospores were abundant and one suspensor always arose from the hyphae and the other from a germinating spore. One species, Acaulopage lasiospora (Drechsler, 1942), did not appear in culture until four weeks after inoculation with leaf mold. The latter taxon forms globose merosporangia that bear numerous appendages on the aerial portion of the spore. Drechsler (1942) described A. gomphoclada which has long, appendaged merosporangia and zygospores that formed as result of lateral cojugation; this fungus was noted 24 days after the plate was inoculated. Other species, Acaulopage lophospora and A. hystericospora (Drechsler, 1946), appeared in culture two to three weeks after inoculation; latter culture also had an extensive colony of A. tetraceros. Drechsler (1947) noted the colony of A. ischnospora 10 days after inoculation; it parasitized the same two amoebae parasitized by other zoopagaceous fungi.

The typical merosporangium is long-bacilliform with a single, unbranched apical appendage, to relatively short and ellipsoid to obovoid with a single appendage to more or less globose or irregular and bearing many short, simple appendages. Other variations include branched spores, as in A. dichotoma (Drechsler, 1945), ovoid or obovoid spores with a single, apical branched appendage ([A. bicornis, A. crobylospora, A. longicornis; Drechsler, 1947, 1955), or long-bacilliform without and apical appendage, as in A. baculispora and A. ischnospora var. pleacra (Drechsler, 1948, 1959).

There has been a large amount of varitiation noted, especially associated with morphology of the merosporangium and its appendage(s), in the 27 species described in Acaulopage. These fungi can appear in culture, when the appropriate host is present, in 10 to 30 days or more.


Ciccarone, C. 1989. Acaulopage tigrina sp. nov. e Drepanoconis divertigastra sp. nov.: due componenti nouvi di generi microfungi poco noti. Micologia Italiana 18:29-32.

Drechsler, C. 1935. Some non-catenulate conidial Phycomycetes preying on terricolous amoebae. Mycologia 27:176-205.

Drechsler, C. 1936. New conidial Phycomycetes destructive to terricolous amoebae. Mycologia 28:363-389.

Drechsler, C. 1938. New Zoopagaceae capturing and consuming soil amoebae. Mycologia 30:137-157.

Drechsler, C. 1939. A few new Zoöpagaceae destructive to large soil rhizopods. Mycologia 31:128-153.

Drechsler, C. 1941. Four Phycomycetes destructive to nematodes and rhizopods. Mycologia 33:248-269.

Drechsler, C. 1942. New species of Acaulopage and Cochlonema destructive to soil amoebae. Mycologia 34:274-297.

Drechsler, C. 1945. Several additional Phycomycetes subsisting on nematodes and amoebae. Mycologia 37:1-31.

Drechsler, C. 1946. Three new Zoöpagaceae subsisting on soil amoebae. Mycologia 38:120-143.

Drechsler, C. 1947. Three zoöpagaceous fungi that capture and consume soil-inhabiting rhizopods. Mycologia 39:253-281.

Drechsler, C. 1948. Three Zoopagaceae that subsist by capturing soil amoebae. Mycololgia 40: 85-105.

Drechsler, C. 1951. Various zoöpagaceous fungi subsisting on protozoans and eelworms. Mycologia 43:161-185.

Drechsler, C. 1955. Additional species of Zoopagaceae subsisting on rhizopods and eelworms. Mycologia 47:364-388.

Drechsler, C. 1959. Several Zoopagaceae subsisting on a nematode and some terricolous amoebae. Mycologia 51:787-823.

Drechsler, C. 1962. A nematode-capturing phycomycete with distally adhesive branches and proximally imbedded fusiform conidia. American Journal of Botany 49:1089-1095.

Duddington, C.L. 1951. Further records of British predaceous fungi. II. Transactions of the British Mycological Society 34:194-209.:

Jones, F.R. 1959. Some Zoopagales from Kenya. Transactions of the British Mycological Society 42:75-89.

Jones, F.R. 1962. New English Zoopagales. Transactions of the British Mycological Society 45:348-358.

Jones, F.R., and M. Peach. 1959. Acaulopage tetraceros Drechsler var. longa sp. nov. Transactions of the British Mycological Society 42:95-96.

Juniper, A.J. 1953. Some predaceous fungi occuring in dung. Transactions of the British Mycological Society 36:356-361.

Park, D. 1971. Acaulopage tetraceros in aquatic habitats. Transactions of the British Mycological Society 57:182-183.

Updated Nov 05, 2007