Scott Namestnik 

Native Plant Profile 
Sedges 
Topped with Pillowy Plumes: 
By Scott Namestnik 
When native plant devotees hear the word 
“sedge,” they likely think of grass-like plants 
with stems that are three-angled and topped 
by non-descript inflorescences. While accurate 
to a degree, the cottongrasses 
(Eriophorum spp.), ranking among 
our most beautiful and showy 
sedges, do not fit the mold. 
Although some species of 
cottongrass have stems that are at 
least bluntly three-angled, others 
have stems that are nearly round 
in cross-section. The most striking 
features of this attractive genus, 
| however, is within the inflorescence, 
where soft bristles develop en 
masse to create cotton-like heads. 
Botanists view the bristles as a 
highly modified perianth, i.e., the 
equivalent of the more familiar 
sepals and petals. Carl Linnaeus, 
r —| who named the genus Eriophorum, 
celebrates this visually striking 
perianth: erio means “wool” 
or “cotton” and phorus means 
“bearing” (Rothrock 2009). 
f™| The genus Eriophorum is 
represented by approximately 25 
species worldwide; depending on 
taxonomic interpretations, there are 
11 or 12 species in North America, 
with seven or eight hybrids (Ball 
& Wujek 2002, Kartesz 2015). 
Six of these species have been 
reported for northern Indiana (five 
until recently; more on that in a bit), 
with one presumed extirpated. Only 

large, rounded tuft of dense, cottony bristles. 
There also are no leaf-like bracts associated 
with this tuft, as there are in Indiana’s other 
cottongrasses. Dense cottongrass grows in 
acidic bogs and was only known to occur 
in two northern Indiana counties (Kartesz 
2015). To our north and into Canada it is 
more common and occurs in various types 
of peatlands (see Arsenault et al. 2013, 
Rothrock 2009, and Smith 2018 for more 
details about each cottongrass species). 
Although one of the Indiana sites has likely 
been destroyed, the other is intact, and since 
dense cottongrass seeds can remain dormant 
for centuries and respond to disturbances 
such as fire and excavation (Rothrock 2009), 
there is hope that this species may someday 
reveal itself as part of Indiana’s flora. 
Rusty cottongrass (E. virginicum) is our only 
Eriophorum without a status as a species of 
conservation concern. This is another bog and 
peatland species, but unlike dense cottongrass 
it is taller, does not form dense tussocks, 
and flowers later in the season (typically 
beginning in late July or August). We're really 
“splitting perianth bristles” when we choose 
the most attractive cottongrass; this one is a 
looker as well. Rusty cottongrass has several 
spikelets per stem (though they have short 
stalks and could appear as a single head at a 
quick glance), each with distinct rusty-tinged 
coloration to the cottony tufts. There are also 
up to five long, leaf-like bracts extending 
from the base of the inflorescence. Rusty 
cottongrass is mostly found in the northern fifth 
of the state, but has a few occurrences as far 
south as Hamilton County. South of Indiana, 
this species occurs primarily along the Atlantic 
Top: The clustered spikelets 
of Eriophorum virginicum, 
One is not considered a species of coastal plain and in the Appalachian Mountains 
conservation concern in the state, (Kartesz 2015). 
as rusty-tinged bristles, yet even it is found exclusively in a The remainder of Indiana’s cottongrass 
develop later in the year rare habitat. species have several white cottony tufts in 
than do those of our other 
The most striking Indiana narrower spikelets on longer, dangling stalks. 
cottongrasses. 
cottongrass species is listed as Narrow-leaved cottongrass (E. 
Bottom: Dense cottongrass state extirpated. Dense cottongrass angustifolium ssp. angustifolium) and tall 
(E. vaginatum var. spissum), (E. vaginatum var. spissum) forms cottongrass (E. viridicarinatum) are both 
a gorgeous species of the distinct tussocks to just over two considered state threatened in Indiana. 
northern boreal zone, may be feet tall, with stems spreading and These two species are similar overall, both 
extirpated from Indiana. ascending, each topped beginning being tall (to over three feet tall), not tussock 
in May by a solitary spikelet with a forming, and having two to four long leaf-like 
12 « Indiana Native Plant Society - Summer 2021 
