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Northwestern Thelypody - Thelypodium paniculatum
Other Names:  Thelypodium sagittatum var. crassicarpum, Thelypodiopsis paniculata

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Species of Concern
Native Species

Global Rank: G2
State Rank: S1
(see State Rank Reason below)
State Threat Score: Unknown
C-value:


Agency Status
USFWS:
USFS: Sensitive - Known in Forests (BD)
Species of Conservation Concern in Forests (CG)

BLM:


 

External Links






State Rank Reason (see State Rank above)
Thelypodium paniculatum has been documented from 5 locations in southwest Montana from 1899 to 2008. Specimens from Beaverhead and Gallatin Counties appear to be correctly identified, though physical specimens need to be re-examined using the treatment by Ihsan Al-Shehbaz in Flora of North America (FNA 2010); it is possible they may better match Thelypodium sagittatum, another Montana Species of Concern plant (Mincemoyer 2022). Ihsan Al-Shehbaz, who is the North American expert on Family Brassicaceae, considers Thelypodium paniculatum 'to be of conservation concern' at the global scale. In Montana, our three Thelypodium species are considered uncommon (Lesica et al. 2012). Plants grow in moist alkaline meadow and wetland habitats which is limited in Montana. Surveys are greatly needed to re-locate populations, validate presence, and collect data on population size, location, habitat condition, threats, and other factors.
 
General Description
PLANTS: Biennial or short-lived perennial herbs, 25-60 cm tall, and glabrous (lack hairs) to sparsely pubescent. Stems grow branched and erect. Sources: Al-Shehbaz in FNA 2010; Lesica et al. 2012.

LEAVES: Basal and stem leaves present, and often glaucous. Basal leaves whither by flowering time. Basal leaf petioles, ciliate, and 2-4 cm long. Basal leaf blades are 2-10 cm long, lanceolate to obovate in shape, and with entire (smooth) margins. Stem leaves are alternately arranged, sessile (lack petiole), auriculate where they clasp the stem, lanceolate to linear-lanceolate in shape, 15-30 cm long, and with entire margins. Sources: Al-Shehbaz in FNA 2010; Lesica et al. 2012.

INFLORESCENCE: A densely flowered raceme that lacks bracts and is terminal on the plant (but does not elongate in fruit). Flowers are lavender to purple. Sepals are erect, ovate to oblong-ovate, (3-) 3.5-5 (-6) mm long by (1-) 1.5-2mm wide. Petals are lavendar to purple, spatulate to broadly obovate in shape, (6.5-) 8-11.5 (-14) mm long by 2.5-5 (-6) mm wide, and margins are not crisped. Petal's claw is slender, narrowest at its base, and strongly differentiated from the blade, (2-) 2.5-4 (-5) mm. Fruit is an erect, linear silique with a short stipe, slightly torulose, and constricted between the seeds. Sources: Al-Shehbaz in FNA 2010; Lesica et al. 2012.

Thelypodium comes from the Greek words of thelys meaning 'female' and podoin meaning 'little foot' and refers to the stipitate ovary that many species in this genus have.

Phenology
Flowering from June to July (Al-Shehbaz in FNA 2010).

Diagnostic Characteristics
Differentiating Montana's three Thelypodium species requires a technical key, such as those by AL-Shehbaz in FNA 2010, Lesica et al (2012), and Giblin et al. [eds.] 2018. Other genera can also appear similar. Thelypodium species have cylindrical siliques while species of Arabis have flattened siliques.

Northwestern Thelypody - Thelypodium paniculatum, SOC
* Stem Leaf: Auriculate-clasping, mostly sessile.
* Inflorescence: Terminal racemes do not considerably elongate in fruit (opened flowers crowded at tip).
* Flower: Petals lavender to purple, 2.5-5 mm wide. Anthers 1-2 mm long.
* Fruit: Siliques often straight, 1.3-2.3 mm wide.
* Seed: Plump.
* Habitat: Wet meadows and streambanks. In the montane zone of Montana.

Slender Thelypody - Thelypodium sagittatum subspecies sagittatum, SOC
* Stem Leaf: Auriculate-clasping, mostly sessile.
* Inflorescence: Terminal racemes do not considerably elongate in fruit (opened flowers crowded at tip).
* Flowers: Petals light to deep violet-purple, 1-3 mm wide. Anthers 2-3 mm long.
* Fruit: Siliques often straight, 0.5-1.2 mm wide.
* Seeds: Flat.
* Habitat: Moist, often alkaline meadows that dry by summer, desert plains to lower mountains. In the montane zone of Montana.

Entire-leaved Thelypody - Thelypodium integrifolium subspecies integrifolium
* Stem Leaf: Bases are cuneate to attenuate, not auriculate, sagittate, or auriculate clasping; sessile.
* Flower: Petals white to purple, 4-7 mm wide
* Fruit: Siliques ascend, 1-3 cm by 0.7-1.1 mm long with a 0.3-2.0 mm long stipe.
* Habitat: Moist to wet, alkaline or saline meadows in the plains, valleys, and montane zones of Montana.

Species Range
Montana Range Range Descriptions

Native
 


Range Comments
Northwestern Thelypody occurs in southwest Montana and extends south and east to Idaho, Wyoming (AL-Shehbaz in FNA 2010). More recent treatments extend the range to Colorado (Giblin et al. [eds.] 2018).

Observations in Montana Natural Heritage Program Database
Number of Observations: 4

(Click on the following maps and charts to see full sized version) Map Help and Descriptions
Relative Density

Recency

 

(Observations spanning multiple months or years are excluded from time charts)



Habitat
Northwestern Thelypody occurs in the Montane zone of Montana (Lesica et al. 2012). Plants grow in wet sedge meadows where the water level may cover basal portions of the plant. It appears to favor meadows and stream bottoms that remain wet for most of the season.
Predicted Suitable Habitat Model

This species has a Predicted Suitable Habitat Model available.

To learn how these Models were created see mtnhp.org/models

Ecological Systems Associated with this Species

Reproductive Characteristics
Plants reproduce by seed.

FLOWERS
A densely flowered raceme that lacks bracts and is terminal on the plant. At anthesis, open flowers are crowed at the tip of the inflorescence.
* Sepals are erect, ovate to oblong-ovate, (3-) 3.5-5 (-6) mm long by (1-) 1.5-2mm wide.
* Petals are lavendar to purple, spatulate to broadly obovate in shape, (6.5-) 8-11.5 (-14) mm long by 2.5-5 (-6) mm wide, and margins are not crisped. Petal claws are slender, narrowest at their base, and strongly differentiated from the blade, (2-) 2.5-4 (-5) mm.
* Anthers are 1-2 mm long.

FRUITS
Fruit is an erect, linear silique with a short stipe, slightly torulose, and constricted between the seeds. Siliques are (1-)1.5-2.5 mm wide.

SEED DISPERSAL
Northwestern Thelypody has lightweight seeds that are probably very easily distributed (Al-Shehbaz 1973). Wind may be an important factor in their dispersal in open habitats such as deserts, flats, and open slopes, but the action of rain wash is perhaps as equally important, if not more important (Al-Shehbaz 1973). Flooding is likely a major means of seed dispersal for species found along streams and riverbanks and in creek beds, and may also be an important vector for plants growing in meadows (Al-Shehbaz 1973).

Stewardship Responsibility

Threats or Limiting Factors
STATE THREAT SCORE REASON
Reported threats to Montana's populations of Northwestern Thelypody are currently assigned as Unknown (MTNHP Threat Assessment 2021). Northwestern Thelypody could be vulnerable to riparian grazing or hydrologic changes based on a current, but a limited understanding of its life history and habitat requirements.

References
  • Literature Cited AboveLegend:   View Online Publication
    • Al-Shehbaz, I. A. 1973. The biosystematics of the genus Thelypodium (Cruciferae). Contributions from the Gray Herbarium No. 204:3-148.
    • Flora of North America Editorial Committee, eds. 2010. Flora of North America North of Mexico. Volume 7. Magnoliophyta: Salicaceae to Brassicaceae. Oxford University Press, Inc., NY. 832 pp.
    • Hitchcock, C.L. and A. Cronquist. 2018. Flora of the Pacific Northwest: An Illustrated Manual. Second Edition. Giblin, D.E., B.S. Legler, P.F. Zika, and R.G. Olmstead (eds). Seattle, WA: University of Washington Press in Association with Burke Museum of Natural History and Culture. 882 p.
    • Lesica, P., M.T. Lavin, and P.F. Stickney. 2012. Manual of Montana Vascular Plants. Fort Worth, TX: BRIT Press. viii + 771 p.
    • Mincemoyer, Scott. 2022. An evaluation of MTNHP observation data on Thelypodium paniculatum. June. Conducted by Scott Mincemoyer, former MTNHP Botanist, Helena, Montana.
    • MTNHP Threat Assessment. 2021. State Threat Score Assignment and Assessment of Reported Threats from 2006 to 2021 for State-listed Vascular Plants. Botany Program, Montana Natural Heritage Program, Helena, Montana.
  • Additional ReferencesLegend:   View Online Publication
    Do you know of a citation we're missing?
    • Culver, D.R. 1994. Floristic analysis of the Centennial Region, Montana. M.Sc. Thesis. Montana State University, Bozeman. 199 pp.
    • Lesica, P., M.T. Lavin, and P.F. Stickney. 2022. Manual of Montana Vascular Plants, Second Edition. Fort Worth, TX: BRIT Press. viii + 779 p.
    • Seipel, T.F. 2006. Plant species diversity in the sagebrush steppe of Montana. M.Sc. Thesis. Bozeman, MT: Montana State University. 87 p.
  • Web Search Engines for Articles on "Northwestern Thelypody"
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Citation for data on this website:
Northwestern Thelypody — Thelypodium paniculatum.  Montana Field Guide.  .  Retrieved on , from