Rhizomyces

Rossi, Walter & Feijen, Hans R., 2018, New species of Rhizomyces (Ascomycota, Laboulbeniales) parasitic on African stalk-eyed flies (Diptera, Diopsidae), European Journal of Taxonomy 474, pp. 1-13 : 9-10

Key to all the Rhizomyces

It should be noted that R. cornutus Thaxt. , R. cucullatus Thaxt. and R. gibbosus Thaxt. are very closely related and the distinguishing characters (in brackets) reported in the key are those given with the original descriptions ( Thaxter 1901, 1918, 1931).

1. Thallus not ramified, usually bearing a single perithecium (very rarely 2) ...................................... 2 ¯ Thallus ramified, bearing more than one perithecium ............ R. ramosus W.Rossi & Feijen sp. nov.

2. Perithecium lacking any outgrowth or bulge near the apex ............................................................. 3 ¯ Perithecium bearing an outgrowth or a bulge near the apex ............................................................ 9

3. Perithecial tip abruptly distinguished and blackened ....................................................................... 4 ¯ Perithecial tip not abruptly distinguished and not blackened ........................................................... 5

4. Basal cell subsigmoid, bearing a depression ...................... R. forcipatus W.Rossi & Feijen sp. nov. ¯ Basal cell not as above .......................................................................................... R. crispatus Thaxt.

5. Thallus never reaching 1 mm in length, not bearing a rounded hausorium ..................................... 6 ¯ Thallus very slender and elongate, exceeding 1 mm in length, bearing a rounded hausorium penetrating the exoskeleton of the host .......................................................... R. canzonerii W.Rossi

6. Thallus not bearing a haustorium penetrating the exoskeleton of the host ....................................... 7 ¯ Thallus bearing a ramified haustorium penetrating the exoskeleton of the host .................................................................................................................. R. ctenophorus Thaxt.

7. Perithecium symmetrical or almost so .............................................................................................. 8 ¯ Perithecium distinctly asymmetrical ..................................................................... R. confusus Thaxt.

8. Perithecial stalk-cell at least 3 times longer than the perithecium; appendage and perithecial apex reaching the same height, more or less ............................................................. ...... R. gracilis Thaxt.

¯ Perithecial stalk-cell about as long as the perithecium; appendage distinctly exceeding in length the perithecial apex ................................................................................................. R. kamerunus Thaxt.

9. Perithecium bearing a rounded bulge or a short outgrowth just below the apex ............................ 10 ¯ Perithecium bearing a divergent, elongate, finger-like outgrowth just below the apex ................................................................................................................ ...... R. circinalis Thaxt.

10. Thallus bearing a ramified haustorium penetrating the exoskeleton of the host.............................11 ¯ Thallus not bearing a haustorium penetrating the exoskeleton of the host ......................................... .............................................................................................. R.tschirnhausii W.Rossi&Feijensp. nov.

11a.Perithecial outgrowth “relatively narrow and tooth-like” .................................... R. cornutus Thaxt. 11b.Perithecial outgrowth “slightly curved outwards, resembling a peaked hood”

...................... ...................................................................................................... R. cucullatus Thaxt. 11c.Perithecial outgrowth “broadly rounded and divergent” ..................................... R. gibbosus Thaxt.