Key 7:

SECTION 7:
Sporangium predominantly cylindrical, fusiform, broadly or
narrowly ellipsoidal, the long axis frequently at a right angle
or slightly inclined to that of the substrate.

shapes


  1. Sporangium fusiform................................................................R. fusus

....................................................................................or R. lagenula *

Sporangium cylindrical, obpyriform, or pyriform......................................2

  1. Sporangium cylindrical.......................................................................3

    Sporangium obpyriform or pyriform......................................................4
  1. Sporangium large, 48-54 micrometers high by 17-22 micrometers diameter;
    on Cladophora

..................................................................................R. messanense

Sporangium small, 4.5-15.5 micrometers high by 2.5-5 micrometers diameter;
on Hyalobryon

..................................................................................R. hyalobryonis

  1. Sporangial wall smooth.....................................................R. anatropum

    Sporangial wall covered by warts.......................................R. verrucosum

*Cejp (1933) described as Rhizophydium lagenula (A. Br.) A. Fisch. an organism on Mougeotia that agrees with R. fusus in the fusiform shape of the sporangium, but which is larger and forms epibiotic resting spores. He considered R. lagenula to be identical with R. fusus.



Return to: KEYS