Accurate identification of the several dozen species of Lomatium is, according to Intermountain Flora, "notoriously difficult.... Some species are highly variable...." Both fruits and flowers are often necessary for identification. Intermountain Flora further observes that "the distinction between Cymopterus and Lomatium is subject to failure". Ordinarily one or more of the Cymopterus dorsal seed ribs have wings; Lomatium seed ribs do not have wings. "Cymopterus newberryi completely bridges the difference. In this species the dorsal wings vary from nearly or fully as large as the lateral ones to poorly developed or even obsolete". Detailed genetic research by Downey, Hartman, et al. indicates that, "Prior emphasis on characters of the fruit in all systems of classification of the group has led to highly artificial assemblages of species.... The variation exhibited by fruit morphology and anatomy among these western N[orth] A[merican] umbellifers severely limits their utility in delimiting genera unambiguously.... In summary, our study confirms that fruit characters are of limited value for delimiting taxa and estimating phylogenetic relationships in this group of western N[orth] A[merican] umbellifers." "Loma" is Greek for "border" and refers to the small wings of the fruit. The genus was named by Constantine Rafinesque in 1819. |
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Lomatium dissectum (Giant
Lomatium) Semi-desert, foothills.
Shrublands, woodlands, openings. Spring. Lomatium dissectum can grow to over four feet tall, but in the Four Corners area it is most often 2-3 feet tall. It is typically found at the lower elevations of the foothills in shrublands and woodlands, in the latter as shown on this page. Leaves (and perhaps even the entire plant) might be mistaken for Ligusticum porteri but the latter has much larger, spreading leaves, consistently puts out a taller flowering stem with white, not yellow flowers, and occurs not only in the foothills but also the montane zone. Flowers surmount a stalk that is up to 40 inches tall. Flowers start in a tight circle and spread in a golden wheel formation over six inches in diameter. (See photographs below.) Thomas Nuttall named this species Leptotaenia dissecta from a specimen he collected in Oregon in the mid-1830s. However, Meriwether Lewis collected this species June 10, 1806 in Idaho along the Clearwater River. Click to read why Lewis' collection is not considered the type. Mathias and Constance renamed this species Lomatium dissectum in 1942. This species is sometimes called Fernleaf Lomatium or Fernleaf Biscuitroot. |
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Lomatium dissectum (Giant
Lomatium) Semi-desert, foothills.
Shrublands, woodlands, openings. Spring. Clusters of tight buds open to attractive sprays of golden yellow flowers and then mature to seed heads 3-6 inches in diameter with fruits from 1/3' to 2/3' long. Seed head wings are 1-2 mm wide. |
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Lomatium dissectum (Giant
Lomatium) Semi-desert, foothills.
Shrublands, woodlands, openings. Spring. Lomatium dissectum grows to four feet tall with robust stems that grow from a taproot that is a foot long and an inch wide. Stems are typically purple to purple-tinged. |
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Lomatium dissectum (Giant
Lomatium) Semi-desert, foothills.
Shrublands, woodlands, openings. Spring. Each of the top two photographs of the four immediately above shows just one leaf, cut numerous times into smaller leaflets which are cut again into fine leaflets as the last two photographs show. The plant at right has leaves that are cut more consistently one more time than those of the plant at left. Leaves are similar to those of Ligusticum porteri but are generally more glossy and not mottled green as those of Ligusticum commonly are. Lomatium dissectum has yellow flowers in the spring; Ligusticum porteri has white flowers in the summer. The ranges overlap in the lower mesas but only L. porteri is found in the higher mountains. Lomatium dissectum is commonly broken into three varieties, one of which is found in the northwest. Varieties eatonii and multifidum are separated primarily on the basis of how finely their leaves are cut. Some experts indicate that the variety found in our area is eatonii and some indicate it is multifidum. Because of this disagreement, I have chosen not to label the variety. |
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Species present in state and native
Species present in state and exotic
Species not present in state
Species present and not rare
Species present and rare
Species extirpated (historic)
Species extinct
Species noxious
Species exotic and present
Eradicated
Questionable presence
