Canada

Origin: Exotic

Regularity: Regularly occurring

Currently: Unknown/Undetermined

Confidence: Confident

United States

Origin: Unknown/Undetermined

Regularity: Regularly occurring

Currently: Unknown/Undetermined

Confidence: Confident

Global Range: Proboscidea louisianica is found in Mexico, and (native or exotic) within a large majority of continental U.S. states (the few exceptions being Wisconsin, North Dakota, Montana, Oregon, and Utah) (USDA-NRCS 1999). In Canada, Proboscidea louisianica is considered exotic and has been documented in Ontario, and possibly in Saskatchewan.

Subspecies fragrans is found in Texas and Massachusetts (Kartesz 1999), is found frequently in the Mexican states of Hidalgo, Jalisco, M?xico, Michoacßn, Quer?taro, San Luis Potos?, and Zacatecas, and is scarce in Veracruz (Taylor 1983). Populations intermediate between subsp. fragrans and subsp. louisianica can be found in Chihuahua, Coahuila, Nuevo and north to Kansas (Taylor 1983).

In spite of the relatively large contemporary range of subspecies louisianica, many suggest that the plant is introduced in their area. Most authors are not highly specific regarding the natural range of this subspecies. Gleason and Cronquist (1963) state that it is native to the southwestern U.S. and may be native as far north as Indiana, but that further north and in the southern states it is probably escaped. Small (1933), on the other hand, states that the plant is native to the Mississippi River valley.

Other reports include: native to the southern U.S. and Mexico (Great Plains Flora Association 1986); perhaps native to the south-central U.S. (Hickman 1993); introduced in Colorado (Weber and Wittmann 1996a); and alien near Chicago (Swink and Wilhelm 1994). It is present but considered to be naturalized in New Hampshire (New Hampshire Natural Heritage Inventory).

Comments: The only native habitat referenced is riverbanks (Fernald and Kinsey 1943, Small 1933). There are many references to the ability of this plant to exploit human-disturbed areas. The plant grows most often in sandy soils, in open areas such as pastures, agricultural fields (Texas Conservation Data Center, Kansas Natural Features Inventory, Mississippi Natural Heritage Program), waste places (i.e., very disturbed areas) (Kentucky Natural Heritage Program, Missouri Department of Conservation), and cattle feedlots (Great Plains Flora Association 1986, Weber and Wittmann 1996b, Hickman 1993, Illinois Natural Heritage Database Program). In Mexico, Taylor (1983) considers the habitat to be ruderal and edges of agricultural fields.

Proboscidea louisianica (Unicorn Plant)
(bees suck nectar or collect pollen; two bee species, Anthophora occidentalis and Centris lanosa, are native to the southern plains, rather than the Midwest; observations are from Thieret in Oklahoma)

Bees (long-tongued)
Apidae (Bombini): Bombus fervida sn/cp (Thr); Anthophoridae (Anthophorinae): Anthophora occidentalis sn/cp (Thr); Anthophoridae (Centridini): Centris lanosa sn/cp (Thr); Anthophoridae (Eucerini): Melissodes communis sn/cp (Thr)

Bees (short-tongued)
Halictidae (Halictinae): Augochorella striata sn/cp (Thr), Lasioglossum spp. cp np (Thr)

Note: For many non-migratory species, occurrences are roughly equivalent to populations.

Estimated Number of Occurrences: 81 to >300

Comments: Widespread in the central and southern United States, but natural distribution unclear. Texas: widespread across the northern half of Texas, hundreds or thousands of populations (Texas Conservation Data Center); Kansas: common throughout the western half of the state (Kansas Natural Features Inventory); Kentucky: occasional (Kentucky Natural Heritage Program); Illinois: weedy in the southern part of the state (Illinois Natural Heritage Database Program); Missouri: uncommon (Missouri Department of Conservation); Indiana: not documented as a wild plant for over 100 years-state rank should be SH or SE (Indiana Natural Heritage Data Center); Arkansas: known from nine counties, not tracked (Arkansas Natural Heritage Commission); Michigan: relatively uncommon weed last collected in 1960-should probably be ranked SE (Michigan Natural Features Inventory); Ontario: not native, should be ranked SE (Ontario Natural Heritage Information Centre); Mississippi: uncommon, ranked SE (Mississippi Natural Heritage Program); Georgia: ranked SE (Georgia Natural Heritage Program); Nebraska: exotic (Nebraska Natural Heritage Program); Wyoming: exotic, known from two collections (Wyoming Natural Diversity Database); Colorado: exotic, most common in southeast, but never abundant (Weber and Wittmann 1996b); Nevada: occurs in far southern Nevada, possibly as an introduction (Nevada Natural Heritage Program). Species reported from New York, Idaho, South Dakota, and Maine by Kartesz (1999), but not known to the respective Heritage Programs (New York Natural Heritage Program, Idaho Conservation Data Center, South Dakota Natural Heritage Database, or Maine Natural Areas Program).

Because Proboscidea louisianica is an annual, populations discovered one year may have disappeared one to a few years later. Also, with a reported habitat mainly of disturbed areas, an occurrence of this species may be lost as time passes, as the habitat becomes further removed from a one-time disturbance event.

A weed of pastures, cultivated fields, and disturbed areas such as feed lots (Texas Conservation Data Center, Kansas Natural Features Inventory, Kentucky Natural Heritage Program, Illinois Natural Heritage Database Program, Missouri Department of Conservation, Michigan Natural Features Inventory, Mississippi Natural Heritage Program).

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 2
Species: 2
Species With Barcodes: 1

Canada

Rounded National Status Rank: NNA - Not Applicable

United States

Rounded National Status Rank: NU - Unrankable

Rounded Global Status Rank: GU - Unrankable

Reasons: Apparently native to Mexico (where reported from several states) and the southwestern United States, and widely established as an exotic elsewhere in the U.S. and in southern Canada. Very little information exists on occurrences of either subspecies in its native habitat. In addition, the native range, particularly of subspecies louisianica, is highly uncertain. As a ruderal, opportunistic species, this plant is well-adapted to disturbance and has colonized many areas that have been greatly altered by human activities. It is possible, and perhaps likely that this species has become somewhat rare in its native setting, since many natural disturbance regimes that have taken place historically are no longer in place. Partial tracking of this species is recommended in order to find high quality occurrences in its native habitat.

Comments: Open, disturbed ground might be more common, or perhaps more frequent on the landscape, than it was prior to Euro-American settlement. Given the habitats reported for Proboscidea louisianica, it is conceivable that its habitat is not threatened in the least. However, it is possible that the specific substrate or chemical properties of Proboscidea louisianica's habitat are not yet known, such that what may now appear to be a landscape advantage of disturbance will eventually be seen more clearly as a threatening situation for this species.

Individual occurrences of this species may, by their very nature, be threatened, as once-disturbed areas tend to change significantly unless the disturbance is repeated. For a more accurate assessment of the threats to this species, its native habitat and natural disturbance regime must be determined, and threats to those native habitats assessed.

A person knowledgeable about the herbal medicinal industry is not aware of commercial trade in this species in the U.S. (McGuffin pers. comm.).

Biological Research Needs: The development of a more thorough conservation assessment of Proboscidea louisianica would probably need to include research in the following areas:

1. What is the original range of the two subspecies of Proboscidea louisianica?

2. Are there habitat differences, and consequently different threats, between the two subspecies?

3.What is the nature of the substrates which favor reproduction or growth of Proboscidea louisianica?

4. What is the historical, native habitat of this species?

5. What is the habitat and distribution within Mexico? [Some information is in Taylor (1983).]

Comments: No records of medicinal uses for this plant have been located, but it has been cultivated for its fruit, which can be eaten like a pickle (Fernald and Kinsey 1943). Taylor (1983) reports that in Mexico, immature fruits are eaten, mature seeds are consumed raw, and children collect the fruits for their strange appearance.

Comments: Native in eastern U.S. s. to northern Mexico; cultivated and occasionally escaped elsewhere (cf. Scoggan, Flora of Canada).

Proboscidea louisianica has two recognized subspecies: subsp. fragrans (synonyms: Martynia fragrans, Proboscidea fragrans), found in the U.S. and Mexico, with U.S. occurrences limited to Texas and Massachusetts; and subsp. louisianica (synonym: Martynia louisianica), comprising the remainder of U.S. occurrences (Kartesz 1999, USDA-NRCS 1999).

Although Kartesz (1999), following Cronquist's classification, merges the Martyniaceae with the Pedaliaceae, some authors believe there are good reasons to maintain the distinctness of these families (e.g., Weakley 1997).