Calochortus

Calochortus is a genus of flowering plants in the lily family. The group includes herbaceous, perennial and bulbous species, all native to North America (primarily the Western United States).

The genus Calochortus includes mariposas (or mariposa lilies) with open wedge-shaped petals, globe lilies and fairy lanterns with globe-shaped flowers, and cat's ears and star tulips with erect pointed petals. The word Calochortus is derived from Greek and means "beautiful grass".

Description

Calochortus flowers have six tepals. Unlike most other Liliaceae, Calochortus tepals are in two series that differ in size and color. The outer three are generally narrower and more sepal-like, while the inner three are larger, usually with bright marks at the base, and are often described as petals. The flowers are borne on a stem that arises from a bulb, generally in the spring or early summer. Flowers can be white, yellow, pink, purple, bluish, or streaked. The insides of the petals are often very 'hairy'. These hairs, along with the nectaries, are often used in distinguishing species from each other.

Species

Distribution and habitat

The genus Calochortus includes approximately 70 species distributed from southwestern British Columbia, through California and Mexico, to northern Guatemala and eastwards to New Mexico, Nebraska and the Dakotas. Calochortus is the most widely dispersed genus of Liliaceae on the North American Pacific Coast. Of these, 28 species are endemic to California.

In 1998, T.B. Patterson conducted a phylogenetic analysis of the genus, dividing it into seven main clades (see Subdivision update below). The study indicated highly localized speciation, so that different floral syndromes were strongly linked to specific habitats, as follows:

• Mariposas: dry grasslands, open chaparral, semideserts
• Star-tulips: wet meadows
• Cat's ears: montane woodlands
• Fairy lanterns: oak woodlands, closed forests.

Taxonomy

History

Calochortus was first proposed in 1814 by Frederick Pursh to accommodate a specimen—C. elegans—received from the Lewis and Clark expedition. In the 1800s, several species were added to the genus; however, much mistakes in naming conventions led to confusion and minimal knowledge gained by the end of the century.

In 1940, Francis Marion Ownbey wrote a comprehensive monograph on Calochortus, referencing morphological evidence, geographical distribution, and his own study of cytological material. Ownbey proposed a treatment dividing Calochortus into three sections (later corroborated by J.M. Beal):

1. Eucalochortus
   • Ten basic chromosomes and two known cases of tetraploidy
   • Includes subsections Pulchelli, Eleganti, Nudi, Nitidi
2. Mariposa
   • Basic chromosome numbers between six and nine
   • Includes subsections Venusti, Macrocarpi, Nuttalliani, Gunnisoniani
3. Cyclobothra
   • Nine basic chromosomes
   • Includes subsection Weediani

In 1985, F.N. Rasmussen developed a new treatment splitting Calochortus from Liliaceae, moving it into a separate family—Calochortaceae—based on chromosomal evidence, septicidal fruit, and a Polygonum type embryo sac formation. Rasmussen found that the basic chromosome numbers of Calochortus vary between seven and twenty.

Subdivision update

In the late 1990s and early 2000s, Thomas B. Patterson and Thomas J. Givnish gathered additional evidence to create a new Calochortus treatment, subdividing it into seven sections and providing reasoning behind Calochortus being separate from Liliaceae. In 1999, Patterson used cpDNA (specifically rbcL and ndhF sequences) isolated from frozen or silica dried leaf tissue to develop a molecular phylogeny, finding that Calochortus should be divided into seven major clades based on geographic location:

• Bay Area
• Pacific Northwest
• San Diego
• Great Basin- Rocky Mountains
• Coast Ranges- Sierra Nevada
• Southwestern California
• Central Mexico

Patterson also determined at the time that concerted convergence and phylogenetic niche conservatism may have confounded the idea that Calochortaceae (Calochortus) and Liliaceae are closely related. In 2002, Patterson and Givnish expanded on these arguments, showing that concerted convergence was demonstrated through independent evolution of characteristics such as bulbs and showy flowers and the distinct differences of these appearing as a result of survival in specific habitats. Regarding phylogenetic niche conservatism, Patterson and Givnish make the argument that this phenomenon is present in the plesiomorphic characteristics of rhizomes, inconspicuous flowers, berries, broad leaves, and reticulate venation.

In 2004, Patterson and Givnish made the shift to lump Calochortus within Liliaceae within their paper per the recommendations of Bremer et al. (2003) and Bremer, Chase, and Stevens (1998). Using similar DNA collection techniques to Patterson (1999), Patterson and Givnish developed a more detailed molecular phylogeny, comparing the seven recently determined sections to Ownbey's original three and finding that Ownbey's Eucalochortus section is monophyletic, Mariposa is paraphyletic, and Cyclobothra is polyphyletic. As a result of their research, Patterson and Givnish (2004) found that the two main factors of Calochortus speciation are:

1. Poor dispersal caused by heavy, passively dispersed seeds
2. Chromosomal evolution allowing different clades to "double up" and radiate sympatrically without hybridizing

Serpentine tolerance

Within Calochortus, almost one-third of species are characterized by ultramafic (form serpentine soils) habitat preferences or specific edaphic requirements, with several being endemic to their environments. Thus, scientists have used serpentine tolerance in understanding evolutionary relationships within the genus. For instance, Patterson and Givnish (2004) created a serpentine tolerance phylogeny. 18 serpentine tolerant species were found (classified by occurring in whole or in part on serpentine soils) and the largest presence of tolerance was found in the Bay Area and Pacific Northwest clades—areas with unusually high numbers of serpentine rocks at the Earth's surface. In addition, Patterson and Givnish (2004) found that 11 out of 18 species displayed only two origins of serpentine tolerance in evolutionary history.

Uses

Culinary

The bulbs of many species were eaten by Native Americans. These bulbs were eaten raw or gathered in the fall and boiled, and the flower buds when young and fresh. They were eaten by the Mormon settlers between 1853 and 1858 when famine threatened new immigrants in the Great Salt Lake Valley, due to crop failures. The bulbs are a starchy food source similar to a potato tuber.

Native Americans called Calochortus "sego". They used it as food, in ceremonies and as a traditional medicinal plant.

Cultivation

Some Calochortus species are cultivated as ornamental plants by specialty nurseries and botanic gardens to sell. The bulbs are planted for their flowers, in traditional, native plant, and wildlife gardens; in rock gardens; and in potted container gardens for those needing unwatered Summer dormancy.

See also

• List of plants known as lily

Notes

References

• "Calochortus". Integrated Taxonomic Information System.
• Treatment from the Jepson Manual (TJM93)
• Gerritsen, Mary E and Parsons, R. Calochortus. Mariposa Lilies and Their Relatives. Timber Press, 2007.
• Pacific Bulb Society

External links

• Media related to Calochortus at Wikimedia Commons
• Data related to Calochortus at Wikispecies
• Calflora Database: Calochortus — all species native to California.
• photos by Mark Egger, Flickriver search for Calochortus many photos of many species
• Jepson Manual (TJM93): Key to California Calochortus species
• Genus overview, Key to North American species
• Gallery of Photos. US and Mexican Calochortus Species and Natural Hybrids