Rolland's bulrush - Trichophorum pumilum
Other Names:
Scirpus pumilus, Scirpus rollandii
Caespitose. Stems terete, 5–25 cm, clustered on thin rhizomes. Leaf blades ca. 0.5 mm wide. Spikelet 3–4 mm long with 3 to 6 flowers; awn of lowest bract shorter than the spikelet. Scales 2.5–3.5 mm long, glabrous, brown with a pale midstripe; tip rounded. Flowers: bristles absent. Achene 1.5–2 mm long (
Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).
Fruiting in July.
After mid-summer,
Trichophorum pumilum looks like a tiny stick with a few little black eggs glued on top. It is most likely confused with species of
Eleocharis, but in these species, the base of the style is enlarged, and the scales are persistent.
Trichophorum cespitosum is a larger plant that forms distinctive tussocks. A hand lens will be necessary for positive identification.
In botanical keys,
Trichophorum pumilum and
Amphiscirpus nevadensis may key closely.
Rolland's Bulrush -
Trichophorum pumilum, Native, SOC
*Perianth Bristles: 0; absent.
*Achene: Tipped with a skinny, short beak (style). Subtended by a scale.
*Scales: Apiculate.
*Spikelets: Solitary, 3-7 mm long. Spikelet is not subtended by a leaf-like bract.
*Stems: Round, less than 15 cm tall.
*Leaves: Less than 0.5 mm wide.
*Habitat: Hummocks in calcareous fens.
Nevada Clubrush -
Amphiscirpus nevadensis, Native, SOC
*Perianth Bristles: 1-6, inconspicuous and shorter than the achene.
*Achene: Not tipped with a beak; style absent. Subtended by a scale.
*Scales: Awn absent.
*Spikelets: Solitary, but usually some plants have at least 2 spikelets; 6-12 mm long. Always with 1 long, leaf-like bract below (subtended) the spikelets.
*Stems: Round, wiry, and erect. Lacks internal cavities.
*Leaves: Basal and on lower stem, 0.5-2.0 mm wide.
*Habitat: Moist to wet alkaline wetlands, but not aquatic.
Calcareous fens in the foothills.
