Scientific Name : Hackelia besseyi
Author : (Rydb.) J.L. Gentry
NatureServe Explorer
Common Name : Bessey's Stickseed
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Taxonomy
Boraginaceae (borage family)
This taxon is included in Ackerfield (2015, 2022). Per Tass Kelso (2014) this species is very similar to H. floribunda and she questions whether H. besseyi is taxonomically distinct.
Ranks and Status
State Rank : S2
State Rank Reason : Hackelia besseyi is known from 9 occurrences in 8 counties in Colorado, USA; 8 of the 9 occurrences are considered historical. This species is considered to be vulnerable to climate change.
U.S. Endangered Species Act : none
Colorado Threatened and Endangered List : none
Other Statuses : none
Description and Phenology
General Description:
Biennial 3-7.5(-ll) dm tall; stem from a short taproot, erect, solitary, reflexed- or spreading-hirsute below, strigose or occasionally hirsute and strigose above, the plant sometimes canescent throughout. Leaves sub-appressed hispid-hirsute or merely hirsute, sometimes hispidulous, the pustulose-bases of the hairs generally evident, the basal leaves withering early, 2-9.5 cm long, (5-)10-17 mm wide, oblanceolate, mostly obtuse and petiolate; cauline leaves strongly ascending, (1.5-)2-8.5(-13) cm long, (2-)5-10(-30) mm wide, oblanceolate to linear-oblong or lanceolate, the lowermost leaves petiolate, acute or obtuse, progressively reduced upward, the bracts evident only at the base of the inflorescence. Pedicels short, 5-10 mm long in fruit. Calyx lobes about 1 mm long, lance-ovate, sub-appressed-hirsute-hispid. Corolla limb blue, 1.5-2.5 mm wide, the tube 0.8-0.9 mm long, slightly shorter than the calyx lobes. Fornices with appendages papillate-puberulent or papillate, broader than long, the protuberance about 2 times broader than long. Anthers 0.4-0.5 mm long. Nutlets 2-2.5 mm long, ovate or ovate-lanceolate; dorsal surface verrucose-hispidulous or sometimes only hispidulous, the intramarginal prickles absent; marginal prickles distinct or slightly connate at their bases, 0.5-1.2(-1.5) mm long, 8-13 on each side, a long and a short prickle alternating.
Look Alikes:
Hackelia besseyi is very hairy, and is a slender plant with flowers that are only 1 or 2 mm in diameter and only a few inflorescence bracts at the bases of the cymes. Hackelia floribunda is less hairy and has shorter, naked cymes (no bracts).
Phenology:
Flowers June-August (Ackerfield 2022).
Habitat
Found on dry hillsides, often in Pinyon-Juniper woodlands (Ackerfield 2022).
Elevation Range:
6,000 - 8,000 feet (1,829 - 2,438 meters)
Distribution
Colorado Endemic:
No
Range:
Hackelia besseyi is known from Alamosa, Chaffee, Costilla, El Paso, Huerfano, Saguache, and San Juan counties, Colorado, USA. Estimated range extent in Colorado of 30,518 square kilometers was calculated in GeoCAT using occurrence data provided by the Colorado Natural Heritage Program (2026). This species can also be found in Arizona, New Mexico, and Texas.
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Threats and Management Issues
This species is considered to be extremely vulnerable to climate change (Handwerk et al. 2015). Other threats specific to the Colorado locations have not been documented.
References
- Ackerfield, J. 2015. Flora of Colorado. BRIT Press, Botanical Research Institute of Texas, Fort Worth, TX. 818 pp.
- Ackerfield, J. 2022. Flora of Colorado. Second Edition. Bot. Misc. 60. BRIT Press, Fort Worth Botanic Garden/Botanical Research Institute of Texas, U.S.A. 861 pp.
- Colorado Natural Heritage Program (CNHP). 2023. Biodiversity Tracking and Conservation System (Biotics 5). Colorado Natural Heritage Program, Colorado State University, Fort Collins.
- Handwerk, J., L. Grunau, and S. Panjabi. 2015. Colorado Wildlife Action Plan: 2015 Rare Plant Addendum. Colorado Natural Heritage Program, Colorado State University, Fort Collins, Colorado, USA.
- Kartesz, J.T. 1996. Species distribution data at state and province level for vascular plant taxa of the United States, Canada, and Greenland (accepted records), from unpublished data files at the North Carolina Botanical Garden, December, 1996.
- Kelso, T. 2014. Email communication from Tass Kelso to D. Anderson, C. Mui, B. Kuhn, J. Handwerk, R. Rondeau Re: Connection for Hackelia besseyi. May 9.
- Neely, B., S. Panjabi, E. Lane, P. Lewis, C. Dawson, A. Kratz, B. Kurzel, T. Hogan, J. Handwerk, S. Krishnan, J. Neale, and N. Ripley. 2009. Colorado Rare Plant Conservation Strategy, Developed by the Colorado Rare Plant conservation Initiative. The Nature Conservancy, Boulder, Colorado, 117 pp.
- Weber, W. A. and R. C. Wittmann. 2012. Colorado Flora, Eastern Slope, A Field Guide to the Vascular Plants, Fourth Edition. Boulder, Colorado. 555 pp.
