Montana Field Guide

Plants: A rhizomatous, colony-forming perennial (SEINet 2017). Rhizomes (underground stems) are slender, with “fleshy fibrous roots” (Nesom 2000). Stems are ascending, 12-40 cm tall, with glabrate (almost smooth) herbage. Above, stems are glandular-pubescent (Lesica et al. 2012).

Leaves: Basal leaves are petiolate and the petiole clasps the stem (Semple 2017); they sometimes wither as the plant develops (eFloras 2017). Stem leaves lack a petiole (Semple 2017) and are somewhat clasping (eFloras 2017). Blades are linear, with parallel veins (SEINet 2017). They are 3-12 cm long and entire (Lesica et al. 2012), with a tiny abrupt point (eFloras 2017).

Inflorescence: Usually 3-10 heads (eFloras 2017) in a panicle, with stipitate-glandular peduncles (Lesica et al. 2012) and small, awl-shaped bracts (Cronquist et al. 1994). Heads are radiate (with both disc and ray florets) and have a flat, glabrous receptacle. The involucre is 5-8 mm high and narrowly bell-shaped (Lesica et al. 2012). Involucral bracts overlap in several series (Cronquist et al. 1994) and have translucent margins appearing gnawed (eFloras 2017). The bracts are linear to lanceolate, glandular, and green but sometimes purplish (Lesica et al. 2012).

(Contribution of Lesica et al. adapted from Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX)

Flowers May-September (Cronquist et al. 1994).

A composite flower (family Asteraceae) of fairly specific habitats with glandular upper parts, linear leaves generally less than 1 cm wide, and at least several flowerheads. Similar to Symphyotrichum campestre (Nutt.) G.L. Nesom, but Almutaster pauciflorus differs in its moister, alkaline habitat and less-leafy, longer branches in the inflorescence (Cronquist et al. 1994, eFloras 2017).

On the plains in wet, usually calcareous soil of fens and wet meadows (Lesica et al. 2012); along streams in dry country (eFloras 2017). Montana specimens have been found in habitats such as shallow wetlands, marshy areas, springs, river-associated meadows, and short grass prairie (CPWNH 2017).

(Contribution of Lesica et al. adapted from Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX)

A halophytic plant - associated with alkaline flats, habitats with clay soils, high evaporation, and seasonal inundation with a distinctive flora (Culver and Lemly 2013). In southeastern Arizona, this plant is only known to occur in rare, marshy, alkaline habitats called cienagas, where it is found with other halophytes and has been considered an indicator species due to its fidelity to this type of habitat (Makings 2013). Considered a Facultative-Wet plant in Montana by the US Army Corps of Engineers – usually but not always found in wetlands (Lesica and Husby 2015). Alberta Environment and Sustainable Resource Development considers seed dispersal weak, on a scale from very weak to very strong (Barber 2015).

The subfamily Asteroideae, to which Almutaster pauciflorus belongs, produces substantial quantities of accessible pollen and nectar. A study of pollen collecting by 60 species of bees in the genus Colletes revealed the Asteroideae as a group was a very important pollen resource (Muller and Kuhlmann 2008). However, predominately specialist bees gathered Asteroideae pollen, while generalist species used it in minor quantities. This corroborates other research finding a tendency towards specialized bee pollination in the Asteroideae. The pollen may have protective chemicals or low protein content, making it difficult for generalist bees to use it.

Flowers: Each head has 15 to 30 female ray flowers, which are white to pale blue and have 5-10 mm long ligules (flattened parts of corollas). There are 40 to 50 perfect (with male and female parts) disk flowers, which are pale yellow and have roughly 5 mm long corollas (Lesica et al. 2012).

Fruit: Achenes are sparsely hairy, obconic, and roughly 1 mm long, with 7 to 10 veins (Lesica et al. 2012). They are golden-brown and are topped with a pappus (modified calyx) of numerous capillary bristles (eFloras 2017).

(Contribution of Lesica et al. adapted from Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX)

Coefficient of Conservatism rating of 7: intolerant of disturbance (Pipp 2015).

STATE THREAT SCORE REASON
Threat impact not assigned because threats are not known (MTNHP Threat Assessment 2021).