California Native Plant Society

Rare Plant Program

New CNPS Online Inventory (8th Edition) Update

Aaron E. Sims

October 2012

The featured change to the CNPS Inventory of Rare and Endangered Plants (the Inventory) is Plummer’s mariposa lily (Calochortus plummerae). Plummer’s mariposa lily is a perennial, bulbiferous herb in the lily family (Liliaceae) that occurs in granitic and rocky areas of many habitats throughout the South Coast and Peninsular Ranges of southern California.

Plummer’s mariposa lily had been included on California Rare Plant Rank 1B (plants rare, threatened, or endangered in California and elsewhere) since the 5th Edition of the Inventory, but was recently downranked to Rank 4 (plants of limited distribution - a watch list). The CNPS Rare Plant Program actively reviews and re-evaluates plants included in the Inventory, and Plummer’s mariposa lily was no exception. It was downranked to watch list category due to an increase in its overall known distribution and frequency.

Although Plummer’s mariposa lily is now a watch list species, that doesn’t mean it should no longer be considered for protection. Its coastal southern California distribution brings with it a lot of threats, which include the following: development, fire suppression, foot traffic, mining, powerline construction, and recreational activities. In addition, Plummer’s mariposa lily is also possibly threatened by vegetation clearing, collecting, road maintenance, and non-native plants.

Due to the threats and uncommonness of Plummer’s mariposa lily, we strongly recommend that it still be evaluated for consideration during preparation of environmental documents relating to CEQA. Furthermore, if populations of Plummer’s mariposa lily decline and/or if threats increase in the future, the CNPS Rare Plant Program and California Natural Diversity Database (CNDDB) will re-evaluate its status at that time.

More information about Calochortus plummerae can be seen in the Online Inventory at www.rareplants.cnps.org/detail/1599, and/or by contacting the author at 916/324-3816, asims@cnps.org.

Calochortus plummerae
Plummer's mariposa lily (Calochortus plummerae) © 2011 Lara Hartley, 1st place winner of the Rare Plant Treasure Hunt photo contest of 2011.

May 2012

The featured proposed new addition to the CNPS Inventory of Rare and Endangered Plants is vernal pool bent grass (Agrostis lacuna-vernalis). Vernal pool bent grass is an annual herb in the grass family (Poaceae) that occurs in mima mound areas within or on the margins of vernal pools. It was recently described by Peterson et al. 2011 (Journal of the Botanical Research Institute of Texas 5(2): 421-426), and is known only from Butterfly Valley (Fort Ord Army Military Base) and Machine Gun Flats (Fort Ord Public Lands) on the Monterey Peninsula.

Vernal pool bent grass (Agrostis lacuna-vernalis)
Vernal pool bent grass (Agrostis lacuna-vernalis) habitat © 2010 David Styer

Vernal pool bent grass (Agrostis lacuna-vernalis)
Vernal pool bent grass (Agrostis lacuna-vernalis) © 2011 David Styer

Vernal pool bent grass was first discovered by Ellen Holms Uhler a few years ago, who showed some of the plants to Randy Morgan, a Santa Cruz area botanist. Unable to determine the identification of the plant, Randall Morgan (along with Dylan Neubauer, David Styer, and Vern Yadon) collected the diminutive grass in May 2010, and submitted some to experts at the Smithsonian Institution for viewing. It was consequently described as new to science!

Vernal pool bent grass is a very rare and local endemic; its known world distribution is estimated to fit roughly within a 1 km circle (D. Styer pers. comm. 2012). Fortunately the plant lies on protected lands; however, vernal pool bent grass is possibly threatened by competition from non-native grasses and other plants, habitat destruction from road building, off road vehicles, livestock grazing, and adverse changes to drainage patterns.

Due to its highly restricted distribution and habitat, as well as possible threats, vernal pool bent grass is currently being evaluated for addition to the CNPS Inventory as California Rare Plant Rank (formerly List) 1B.1 - plants rare, threatened, or endangered in California and elsewhere; seriously threatened in California.

More information about Agrostis lacuna-vernalis can be obtained by contacting the author at 916/324-3816, .

 

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