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KEY TO THE FAMILIES OF MUCORALES 1

(See Key to Genera of Mucoraceae below)

 

1a-  Sporocarp present, containing sporangia, zygospores or azygospores-------------------------------------------------------- Endogonaceae

 

1b-  Sporocarp lacking---------------------------------------------------------------------------------------------------------------------------------- 2

 

 

2a-  Sporangia all columellate and alike--------------------------------------------------------------------------------------------------------------- 3

 

2b-  Columellate sporangia present or absent; noncolumellate-------------------------------------------------------------------------------------- 4

 

 

3a-  Sporangial membrane thin, fungaceous; sporangiospores liberated by breaking up of sporangial wall; zygospores rough, suspensors

      usually not tong-like----------------------------------------------------------------------------------------------------------------- Mucoraceae

 

3b-  Sporangial wall densely cutinized above, entire sporangium violently discharged or detached as a whole from sporangiophore;

      zygospores smooth, suspensors tong-like-----------------------------------------------------------------------------------------Pilobolaceae

 

 

4a-  Terminal sporangium columellate, multispored, or sometimes replaced by a sterile spine or with neither present; sporangiola

      few or 1-spored borne on branches of the same sporangiophore---------------------------------------------------------------Thamnidiaceae

 

4b-  Columellate sporangia lacking (except in Choanephoraceae); imperfect stage representee by noncolumellate sporangia, sporangiola,

      merosporangia or conidia, or some combination of these structures--------------------------------------------------------------------------- 5

 

 

5a-  Asexual state represented by merosporangia or conidia borne upon phialides on a sporocladium------------------------------------------ 6

 

5b-  Merosporangia lacking; conidia not borne on phialides on a sporocladium------------------------------------------------------------------- 7

 

 

6a-  Merosporangia borne on swollen tips of sporangiophores, at first cylindrical, then forming a single row of sporangiospores,

      simulating a chain of conidia------------------------------------------------------------------------------------------------ Piptocephalidaceae

 

6b-  Imperfect stage with only conidia; conidia borne on phialides which in turn are borne upon a sporocladium; sporocladia often on a

      branch  or directly upon a conidiophore-------------------------------------------------------------------------------------------Kickxellaceae

 

 

7a-  Sporangiola or conidia borne on swollen tips (columellate sporangia also present in some genera); zygospores naked------------------- 8

 

7b-  Sporangia, if present, without columellae; sporangiola and conidia, when present, borne singly, not on swollen tips of sporophores;

      zygospores imbedded in a thick hyphal matrix------------------------------------------------------------------------------- Mortierellaceae

 

 

8a-  Genera forming conidia only; with zygospores formed as in Mucor------------------------------------------------- Cunninghamellaceae

 

8b-  Genera always possessing sporangia and sometimes conidia; zygospores not formed as in Mucor-------------------- Choanephoraceae

 

= = = = = = = = = = = = = = = = = = = =

 

KEY TO THE GENERA OF THE MUCORACEAE

 

1a.- Sporangia flask-shaped with a distinct spherical venter and a long neck.------------------------------------------------------- Saksenaea

 

1b.- Sporangia not flask-shaped.------------------------------------------------------------------------------------------------------------------- 2

 

 

2a.- All sporangia pyriform and with a definite apophysis; sporangia borne from stolons but typically not opposite the rhizoids..  Absidia

 

 

2b.- All sporangia spherical; if stolons present, then sporangiophores opposite the rhizoids.----------------------------------------------- 3

 

 

3a.- Sporangia with a definite apophysis.-----------------------------------------------------------------------------------------------------------4

 

3b.Sporangia without an apophysis.---------------------------------------------------------------------------------------------------------------- 5

 

 

4a.- Sporangiophores formed mostly on stolons opposite the rhizoids---------------------------------------------------------------- Rhizopus

 

4b.- Sporangiophores not on stolons.----------------------------------------------------------------------------------------------------- Spinellus

 

 

5a.- Sporangiophores usually on stolons with rhizoids.----------------------------------------------------------------------------- Actinomucor

 

5b.- Sporangiophores not on stolons.-------------------------------------------------------------------------------------------------------------- 6

 

 

6a.- Sporangiophores regularly dichotomously branched; sporangia all of the same size; homothallic.--------------------------- Syzygites

 

6b.  Sporangiophores at least partly dichotomously branched; large terminal sporangia and smaller sporangia on branches; homothallic.

       ------------------------------------------------------------------------------------------------------------------------------------ Dicranophora

 

6c.  Sporangiophores irregularly divided or simple ----------------------------------------------------------------------------------------------- 7

 

 

7a.- Sporangiophores branched with all the branches bearing sporangia circinately.------------------------------------------------ Circinella

 

7b.- No sporangia or not all the sporangia on branches borne circinately. -------------------------------------------------------------------- 8

 

 

8a.- Large sporangiophores over 80 mm. high with a metallic luster, unbranched; suspensors with branched, finger-like projections

          ------------------------------------------------------------------------------------------------------------------------------------ Phycomyces

 

8b.- Sporangiophores shorter, or, if 80 mm. then branched and without metallic luster; suspensors usually unadorned. ------------------ 9

 

 

9a.- never parasitic upon other members of the Mucorales; suspensors unadorned. --------------------------------------------------------- 10

 

9b.- gall-forming parasites upon other Mucorales; suspensors with finger-like projections. --------------------------------------- Parasitella

 

 

10a.- Zygospores constantly on short side branches of the sporangiophores; homothallic; heterogamous. ------------------ Zygorhynchus

 

10b.- Zygospores on separate hyphae, seldom upon sporangiophores; mostly heterothallic; isogamous. ----------------------------- Mucor

 

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1 -- Derived from University of Wisconsin, Madison Botany Dept.