MELANTHIACEAE

MELANTHIACEAE View in CoL View at ENA

Toxicoscordion : Toxicoscordion nuttallii deleted from the flora of Mississippi and notes on its status in the easternmost states of its range.

Primary author:John Michael Kelley

Toxicoscordion nuttallii (A. Gray ex S. Watson) Rydb. View in CoL ( Melanthiaceae View in CoL ) is a bulbous herb with well-documented presence in the states of Arkansas, Kansas, Louisiana, Missouri, Oklahoma, and Texas. It typically inhabits tallgrass prairies, glades, and woodlands ( Schwartz 2003; Weakley 2020) and is considered to be restricted to undisturbed native habitat ( Ladd & Thomas 2015). While considered G5 or Globally Secure ( NatureServe 2020) and unranked in four states in its distribution because of being at least relatively secure in each of those jurisdictions, it is ranked S1 (critically imperiled) in Louisiana and Missouri ( NatureServe 2020).

After finding a new population in Caddo Parish, Louisiana, I began searching the available literary and herbarium records, requesting accounts from botanists, and revisiting occurrences at the eastern edge of the species’ range. I made notes on habitat preferences to aid in further searches for the species in Louisiana and Mississippi.

Kartesz (2015) listed Mississippi within the range of T. nuttallii based on a specimen supposedly housed at LSU and digitized on the herbarium database SERNEC (John Kartesz, pers. comm.). Based on Kartesz (2015), Weakley (2020) attributed the species as occurring in Mississippi. I encountered this specimen online and found that the label data did not appear to match the specimen, and that the county where it was supposedly collected had no suitable habitat, suggesting that the record was dubious. When I requested information from LSU, it was discovered that a T.nuttallii specimen from Caldwell Parish, Louisiana, had been confounded with a Carex L. specimen from Tunica County, Mississippi. I found no other vouchers or accounts for T.nuttallii in Mississippi, thus the species should be presumed to not be a component of the flora of Mississippi. Mississippi has many calcareous prairies and woodlands, but no evidence yet supports the presence of this plant east of the Mississippi River. The extensive digitization of specimens has made distributional information more available, but records should always be additionally vetted to ensure their accuracy.

For Missouri, I found one specimen of Camassia scilloides (Raf.) Cory misidentified as T. nuttallii on SERNEC and one specimen that was collected in Hays County, Texas, filed incorrectly under Texas County, Missouri. I brought these issues to the attention of the appropriate data managers via email. In Missouri, the species is known only from two limestone glades, one on private land and the other on USFS land, neither resurveyed in the last two decades and with known recorded populations of fewer than 100 plants (Mallissa Briggler, MONHP botanist, pers. comm.). Considering the very small populations, the S1 rank appears correct.

The Arkansas Natural Heritage Commission currently considers T. nuttallii “too common to track,” but the species is under consideration for tracking in the future (Theo Witsell, pers. comm.). The largest populations may occur at Fort Chaffee, but other seemingly viable populations occur in the eastern Ozark dolomite glades and similar habitats across the state.The flora of dolomite glades in northeastern Arkansas has similarities to that of the prairies of northwestern Louisiana, with roughly half of the species present being shared by the two systems (pers. obs.). The species apparently responds favorably to fire in reclaimed grasslands. Hogs may be damaging populations across Arkansas because they appear to be searching for the subterranean parts of this and other bulbous species ( Theo Witsell ANHC, pers. comm.). The proximity of some Arkansas populations to Missouri populations makes them ideal donor sites to bolster Missouri’s low numbers. While no formal rank has been given, and data are incomplete, a working assessment suggests T. nuttallii is S3 S4 (near threatened to apparently secure) in Arkansas.

Louisiana’s known populations are within calcareous prairies or the woodlands adjacent to them. The two prairie systems that are known to support T. nuttallii populations are the Morse Clay (Caddo and Bossier parishes; six populations) and the Copenhagen (Caldwell Parish; one population) Jackson series. These systems are under study to clarify and improve the classification of their communities for conservation planning. New Morse Clay prairies have recently been discovered in Webster Parish, Louisiana, and in Columbia County, Arkansas.High-quality remnants similar to the Copenhagen prairies have recently been delineated in LaSalle Parish and are being surveyed floristically (Kelley & Reid, in prep.); these sites may yield new stations for T. nuttallii in the state.

I revisited known populations of T. nuttallii in the Morse Clay prairies to determine their current population status. I found two Caddo Parish stations presumably extirpated from degradation (last observed 1977 and 1979) and observed no plants at a third, relatively intact station (last observed 1973). The new Caddo Parish population (observed 2020), two in Bossier Parish (last observed 2017 and 2020), and the Caldwell Parish population (last observed 1998, owned and managed by The Nature Conservancy) have been recently observed and are presumed extant, though the largest I observed had fewer than 500 plants. The species is at moderately high risk of being extirpated if its habitat is managed improperly. Because of the small number of populations, their small size, their vulnerability to loss if management is not appropriate, and documented loss of some populations, an S1 (Critically Imperiled) rank for T. nuttallii in Louisiana remains warranted.

Additional surveys with the goal of locating new populations are needed for this species in Louisiana, southern Arkansas, and in non-glade habitats; the following comments and recommendations may assist. I have observed Nemastylis geminiflora Nutt. and Camassia scilloides to be frequent companions to T. nuttallii in Louisiana and Arkansas. The habitats in Louisiana are often moist streamside woodlands with Quercus similis Ashe , Crataegus spp. , and diverse herbs. Populations in calcareous woodlands seem to respond favorably to frequent fire, sometimes supplemented by physical canopy reduction. At least two Louisiana stations have been mowed regularly, but stations I considered extirpated may have been lost to this unnatural regime. Any populations found should be reported to the appropriate Natural Heritage program with information on the natural communities at the site and their edaphic conditions, and the number and vigor of individuals.