The genus Cladium of Renfrew County:
A comparative study

By Grant A. Bickel, 2020

Genus Cladium P. Browne, Twig-rush

Cladium mariscoides is the only species representating the Cladium genus in Canada.

Cladium mariscoides (Muhl.) Torrey, Smooth twig-rush

Cladium mariscoides is common in Renfrew County, found in standing water along the shores of ponds and lakes. Its achenes are quite distinctive, looking like miniature acorns without caps.

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Achenes and scales of Cladium mariscoides

Figure 1. Achenes and scales.
Inflorescence of Cladium mariscoides

Figure 2. Inflorescence.
Cladium mariscoides in natural setting

Figure 3. Habit in natural setting.
Cladium mariscoides in bloom

Figure 4. Blooming inflorescence.
Mature Cladium mariscoides

Figure 5. Mature inflorescence.
Cladium mariscoides in natural setting

Figure 6. Habit in natural setting.
An occurrence map of Cladium mariscoides in Renfrew County

Figure 7. Occurence map for Renfrew County and surrounding area.
Verified records for specimens from Renfrew County
Accession # Collector Date
CAN 585259 D.F. Brunton 1999-July-22
CAN 585364 D.F. Brunton 1998-October-06
CAN 526959 A. Vogg 1985-July-15
CAN 526913 A. Vogg 1985-July-14
CAN 522115 J. Reddoch 1983-October-02
CAN 468811 S.J. Darbyshire 1982-August-21
CAN 570123 T.C. Brayshaw & M.I. Moore 1966-July-17
CAN 570124 T.C. Brayshaw 1962-October-21
DAO 256190 J.A. Calder & I. Kukkonen 1959-September-24
DAO 256172 W.G. Dore 1949-August-04
DAO 256168 W.G. Dore & A.J. Breitung 1948-September-19
DAO 256170 W.G. Dore & A.J. Breitung 1948-September-16
DAO 256169 A.J. Breitung 1948-August-01
CAN 570122, DAO 256171 A.J. Breitung 1948-July-27