THE GENUS PYTHIUM - An-Najah National University

III. KEY TO PYTHIUM SPP. ISOLATED IN THE WEST BANK AND GAZA
STRIP.
Living isolates of the species so far reported from the West Bank and Gaza
Strip were examined. Illustrated descriptions are given for those marked (*) in
the key. The other species included in the key are noted briefly.
2(1)
3(2)
4(3)
5(4)
6(5)
7(6)
8(5)
Oogonia and antheridia produced in single
cultures Oogonia and antheridida not or scarcely
produced in single cultures
Oogonial wall smooth or occasionally with few
projections
Oogonial wall ornamented with spines
SPECIES WITH SMOOTH OOGONIA
Sporangia filamentous, inflated or not
Sporangia globose or subglobose, proliferating or
not (sometimes only hyphal swellings present)
Sporangia not or slightly inflated
Sporangia inflated, lobulated or toruloid
SPORANGIA FILAMENTOUS, NOT OR SLIGHTLY INFLATED
Oospores plerotic
Oospores aplerotic
Oogonia usually with 1-3 papillae, 15.3± 0.4 -95%
c.1. urn diam; antheridia usually lacking
Oogonia smooth; antheridia present
Oogonia 21.6± 0.7)Jm diam; antheridia diclinous,
sometimes branched; hyphal swellings occasionally
present
Oogonium l7.2± 0.6-95% c.1. urn diam;
antheridia monoclinous and diclinous, not
branched; hyphal swellings absent
Oogonia 26.6± 1.4-95% urn diam, when
elongated then 44-110 urn long, globose, sac
shaped or trumpetshaped, usually with a long
thick neck-cell
Oogonia 19.7± 0.8-95% c.1..um diam, globose or
pyriform, thick neck-cells absent
10
2
47
3
17
4
25
5
9
6
8
P. papillatum*
7
P.lutarium
P. monospermum*
P. coloratum*
P. pachycaule