Lomatium Identification
Mostly non-technical guide for species found in western and central Washington State. There are several other species in southeastern Washington that I have not yet observed and are not listed. Be sure to follow links for species - good pictures and sometimes more detailed description and comments. I also have a partial and very simplified key. This guide is somewhat idiosyncratic and mostly focuses on specific characters that I find useful in the field rather than a comprehensive description or key.
Useful non-technical slide show: Slides (this source says that seed dispersal is by water and rodent cache, but I would add wind dispersal, at least for species with fruit wings in the windier parts of central Washington, which sure look they are designed to be dispersed by high winds (winged fruits). By molecular studies, Lomatium and Cymopteris (and a few Tauschia and others) are extensively interdigitated, which appears not to have fully penetrated to formal naming. George et al 2014 Phylogenetic Analysis Reveals Multiple Cases of Morphological Parallelism and Taxonomic Polyphyly in Lomatium .
A number of new Lomatium species are present in Washington, some of them just published or in the process of description and publication, so if you see one that looks really unusual, I suggest pinging Mark Darrach of the Burke Herbarium (type "@lomatiumlarry" in a comment box).
Some identification guides suggest crushing some leaves, but all of the species I have tested seem to smell roughly the same of cedar and turpentine, so smell can be useful to identify as Lomatium but not among species (on the other hand I do not have a discriminating nose).
Photo tips
A few Lomatiums can be identified by a single photo but most cannot.
Take several photos, possibly including:
1) the overall plant (not just the flower) and perhaps a text comment on size
2) the leaf structure (holding your hand or a sheet of something behind the leaf helps)
3) the underside of the secondary umbel (the base of each little cluster of flowers)
4) as close as you can get to a leaflet and the flower stem (some species have very short hairs). Newer phones often have macro capability that is quite good.
5) a shot toward the base trying to focus on whether leaf stems come straight out of the ground (basal leaf) or branch off from the flower stem above ground (cauline leaf).
6) Do NOT bother posting lots of shots of the top of the flowers: one is plenty because other than color and general arrangement of the umbel they all look nearly identical. For the Computer Vision Model multiple shots are likely even detrimental because they will dominate the training set.
Guide
[ ] names mean "easily confused with"
Cymopterus terebinthinus - [papilioniferum] except when fruiting looks a lot like a medium to large leafy yellow Lomatium with highly dissected shiny leaves with a sharp-tipped leaflet. In WA state often found in dry sandy (sometimes rocky) soils and the slightly sticky leaves and stems may have sand grains stuck on them. Mature fruit with multiple wing-like ridges; even during late flowering the basic ridged structure is apparent at the base of each flower. Flowering..
Tauschia stricklandii - small with yellow flowers and wide entire leaflets, narrow endemic found only in a few subalpine meadows, most notably around Mount Rainier. Leaves arise from the base and consist of 5 glabrous entire ovate to eliptic leaflets (sometimes 3 or 5). The immature fruit looks rather like a tiny striped mellon (~0.5 cm long). Plant configuration and young fruits. In flower. Mature fruits.
L. ambiguum - [geyeri, triternatum] yellow medium small to tall lanky glabrous Lomatium with divided leaves mostly projecting from floral stem with prominent bracts enclosing base of leaf. Leaflets usually stubby and often looking ill-formed with irregular sized rounded lobes (reminiscent of moose antlers Observation). Flowers bright yellow in mid spring, no involucre or involucel (umbel bracts), umbels usually multiple and well separated umbelets when mature. Fruits usually start rather long and narrow and mature to slightly wider looking with narrow wings and about 1 cm long. Lacks short fuzzy flower stem hairs characteristic of L. triternatum, but requires good closeup photo or hand lens. Mostly absent from south central WA, where triternatum is common. Observation.
L. brandegeei - [thompsonii] montane, medium to largish, deeply divided leaves, medium to fairly narrow width leaflets with distinctive highly visible veination, yellow flowers, glabrous flower stem, oval curved fruits usually held out to the side or declining rather than upright, often disorganized in orientation. Very common in developed serpentine soil in Wenatchees (and more widely in dry side central to northern Cascades) despite being listed as vulnerable. Fruits, Observation , and Observation. Closeup of leaf showing reticulate veination.
L. canbyi - often on shallow lithosol, small early flowering white with distinctive widish leaflets, usually glaucous/grayish/bluish and held close to flat in plane of leaf, often quinate division, often with a tiny cusp on a rounded leaflet tip. Leaves glabrous but often with a minutely roughened surface. Contrary to Burke, I find the involucel lobes are often quite visible, but sometimes thin and whispy (Burke says "involucel bractlets narrow and inconspicuous"). Flower stems glabrous and usually brownish red. Mature fruits very flattened and green with prominent wings and red edges (eventually brown). Mostly on Columbia Plateau from low to moderate elevations. Observation and Observation.
L. columbianum - [Lomatium novum 3] large and bushy with rosy-pink flowers, unmistakable when in flower and even after. Huge fruits for a Lomatium, oval and thick with substantial wings obvious only at dry maturity. Observation and Observation and Fruits.
L. cous - small yellow, not yet observed by me. Found in the southeast corner of Washington (and elsewhere). Burke.
L. cowichensis - see novum 3 below.
L. cuspidatum - narrow range, Wenatchee serpentine specific, distinctive leaves, dark purple/red flowers. Mature fruits somewhat flattened but have no wings or narrow wings. Detailed description.
L. dissectum - [multifidum] large bushy, dark red/purple (sometimes yellow) flowers, wider leaflets on average than L. multifidum. Leaflets appear roughened (scabrous) due to very short hairs or papillae. Fruits have no obvious stalk, look like a radiating bunch, unlike multifidum. Fruits. Flowering.
L. farinosum - very early flowering, often on shallow lithosol, very small yellow (or white?) glabrous with narrow branched leaves. Distinctive leaves with each side branch in three parts (biternate), linear leaflets folded into V- to U-shaped cross-section, sometimes flattened out some when older. At maturity most leaflets have a tapered reddish/brown tip (photo, also found in L. triternatum). Involucel lobes prominent and often fused at bases (photo). Mature fruits somewhat flattened but have narrow wings. All the ones I have seen are on scabland (shallow lithosol) where they can be locally abundant. Observation (early) ; Observation (mid-flower).
L. frenchii - [watsonii] pprobably will be the name of a glabrous L. watsonii-like species present in south central WA in the east side mountains, around Naches, east Wenatchees, and probably elsewhere. Comparison of L. watsonii and possible L. frenchii leaves.
L. geyeri - [gormanii, piperi] medium small, white flowers with fairly narrow leaflets, larger and more leaves than L. gormanii and usually growing in deeper soil on the Columbia Plateau and hills. Fruits genus-typical with prominent wings. Has a distinctive double root bulge (Burke), sometimes even multiple swellings. I am fairly sure this is also common in the high eastern Wenatchees in exposed sites including rocky soils (but not shallow lithosol). Observation.
L. gormanii - [piperi] very early flowering, widespread tiny plant, white flowered, glabrous, with no flower stem leaves (unlike piperi), sometimes locally abundant on shallow lithosol. Mature fruits oval and somewhat flattened but with very narrow wings. There seems to be no consensus on how to distinguish this from piperi, with conflicting comments in various official reports. Most likely if the flower stem has a prominent leaf it is piperi (but they may not always have them) and most likely if the developing fruit has a finely "scurfy" or scabrous roughened surface it is gormanii (photo) and if shiny smooth (photo) it is piperi. Interestingly DNA sequence analysis shows these two species are not closely related, indicating convergent evolution. Observation. Active discussion of gorperi (gormannii and piperi).
L. hallii - small to medium, yellow flowers, found in Oregon including Siskiyous. Observation.
L. howellii - uncommon, distinctive wide toothed leaflets, mostly on Klamath serpentine. Observation.
L. klickitatense - [papilioniferum] large puffy finely dissected, leaflets longer than L. papilioniferum, yellow flowers. Observation and Observation.
L. knokei - very rare medium small yellow with narrow leaflets. Possible observation.
L. laevigatum - very narrow range mostly in Columbia Transect, large yellow with long leaflets, involucel nearly absent. Observation.
L. leptocarpum (L. bicolor leptocarpum) - not yet observed by me, rare in Washington. Observations by others.
L. linearifolium - [gormanii, piperi] very similar to L. gormanii, main obvious difference is elongated flower head. I have not observed this one. Mostly in southeastern WA. Burke.
L. lithosolamans - very early flowering white, on shallow lithosol, uncommon but possibly locally abundant on extreme lithosol, usually with very few leaflets that are accutely V-shaped in cross section unlike other early salt and peppers. Leaves few and rather fleshy and often persist and retain shape until completely dry and brown. Flower umbel sometimes appears elongated. Fruits are elongated and ridged but lacking obvious wings, usually turning purplish near maturity. Endemic to Kittitas/Yakima Counties. Observation by kimberlyq and (fruiting/dried leaves) observation.
L. macrocarpum - widespread and common especially on Columbia Plateau, sometimes on shallow lithosol, medium sized, ground hugging when in early flower (later more erect and when in fruit the stems are often very erect, towering over the shriveling leaves), easily recognized green-white flowers with long white stamen filaments (often yellow flowers further south), velvet-hairy floral stalks and bracts, cusped leaflet tips, sometimes has quinate leaf division, ASYMMETRIC secondary umbel bracts (involucels) longer on outer hemisphere. Fruits large (macrocarpum) with prominent wings, but L. columbianum are even larger.Observation.
L. martindalei - moist montane, small, usually prostrate, wide leaflets, yellow flowers. On west side of Cascade Ridge, or close such as Goat Rocks or Mount Aix. Can be confused with Sanicula graveolens (look at the umbel bracts) and L. watsonii (look for hairy leaves). Observation.
L. multifidum - [dissectum, thompsonii] large bushy highly dissected leaf, yellow flowers (sometimes dark red), very similar to L. dissectum but usually has narrower leaflets. Often has minute hairs or papillae on leaves (scabrous). Involucel variable from long prominent bracts that extend past flowers to modest and lanceolate. Fruits with prominent stalk, unlike dissectum. Fruits. Flowers.
L. nevadense - central to southern Oregon and further east and south, somewhat similar to canbyi.
L. nudicaule - [novum 1, see below] sometimes montane, medium to large, unmistakeable very broad leaflets, yellow flowers, large swollen base where umbels branch. Leaflets sometimes have toothed tip.Observation.
L. papilioniferum - [C. terebinthinus] large showy yellow flowered (smaller in stunting habitats), distinctive highly dissected leaves with short narrow terminal leaflets, often appearing nearly cylindrical until you look you closely. Leaf dissections appear angular, leaflets often rough looking or with very short hairs, NOT shiny. Foliage looks "frothy" from a distance and has strong 3D shape when closer. Immature fruit bulbous (sometimes almost spherical), gradually becoming quite flat at maturity with prominent wings. One of few on rock cliffs, extremely common in Columbia transect and widespread in eastern WA. Flowering.
L. piperi - see L. gormanii.
L. quintuplex - on shallow lithosol, small yellow flowered with highly dissected leaves in a strongly 3-D shape and slightly cusped nearly cylindrical leaflets (photo), in marginal rocky sites where it is often very abundant. Involucel lobes narrow. Mature fruits somewhat flattened but have very narrow wings. Narrow range in Kittitas and Yakima counties. Observation.
L. refugianum - [roneorum, but ranges distinct] not yet published. Yellow flowered, highly dissected glaucous to medium green leaves with short slightly thickened leaflets. Involucels narrow to inconspicuous or absent. Flower stems glabrous. Leaflet and leaflet stems with very short triangular papillae making the surface look rough if you look closely. Fruit oblong and glabrous. Probably a narrow endemic, type locality Bethel/Burnt Mountain Ridge east of Mt. Rainier near Naches. Observation and Closeup of tiny papillae.
L. roneurum - [refugianum, but ranges distinct] rare, distinctive thick leaflets, medium sized, yellow flowers sometimes with red flush, narrow range on Chumstick and adjacent gneiss rocks. Observation and Observation.
L. simplex - [triternatum] hard to distinguish from narrow-leaved forms of L. triternatum. lanky medium sized yellow, two to three times ternate narrow leaflets, often very long leaflets. Velvet-like hairy. Does NOT have leaves growing out of flower stem (unlike many triternatum). Observation.
L. suksdorfii - not yet observed, south central WA, medium to large bushy yellow flowers. Highly divided leaves with broad leaflets, somewhat reminiscent of L. brandegeei. Huge flat fruits with prominent wings at maturity.
L. thompsonii - [brandegeei, multifidum] narrow endemic in east Wenatchee Mountains. Medium to large bushy yellow, elongated erect fruits. Rather lacy looking with highly branched leaves and narrow flat leaflets. Very short velvety hairs on all stems and fruit (might need a hand lens or very closeup photo). Fruit somewhat elongated and held erect, unlike brandegeei. Flower stems arise from a sheath above ground at the base of a leaf. Mostly in East Wenatchee mountains above Wenatchee in Blewett Pass to Stuart Ridge area. Can be confused with L. brandegeei or L. multifidum. Observation.
L. triternatum - highly variable in size and leaflet width. Very common east of the Cascade ridge, often the only Lomatium in dry meadows, where it can be abundant. Small to medium sized, yellow to pale yellow, narrow leaflets (narrowly lanceolate to nearly linear, except broader in var. brevifolium). Narrowest-leafed forms hard to distinguish from L. simplex. Dense very short hairs on flower and umbel stems (may be hard to photograph because they are so short), sometimes has reduced leaf on flower stem (unlike simplex), often disorganized looking leaves, lacking the specific 3-D structure found in many Lomatiums. Usually only a few leaves, but sometimes bushier looking with many leaves but still short. Observation.
L. tuberosum - on coarse basalt talus/scree, rare adorable plant, very distinctive terete foliage often with bluish color, dark yellow flowers. Observation and immature fruits.
L. utriculatum - small lowland coastal, yellow flowers early spring, highly dissected leaves with narrow leaflets, but somewhat variable. Secondary umbel bracts wide and almost leaf-like.Observation and umbel details.
L. watsonii - [frenchii] small yellow to very pale yellow flowered, hairy leaves, somewhat similar to L. canbyi (widespread) and L. cous (found only in SE corner). Mostly from Wenatchee Mountains to south central WA often at high elevations among large rocks or on rocky soil on exposed sites. Ground hugging while in flower (at least in the windy exposed sites where I have seen it). Leaves with dense short hairs (there is also a glabrous form that will probably be split off as L. frenchii). Partially or fully fused involucel. Flower stems sometimes wooly/hairy, umbel stems and immature fruits often hairy. Burke. Observation.
Lomatium novum 1 - nudicaule-like https://www.inaturalist.org/observations/219212523
Lomatium (possible) novum 2 - knokei-like https://www.inaturalist.org/observations/218263367
Lomatium (possible) novum 3 - columbianum-like but genetically distinct, will probably be named cowichensis. https://www.inaturalist.org/observations/221923154
Lomatium novum 4 - one observation by Adam Schneider, largish plant with relatively wide leaves, possibly on serpentine: https://www.inaturalist.org/observations/229184067
Others that are potentially new:
https://www.inaturalist.org/observations/168949480
https://www.inaturalist.org/observations/220761471
https://www.inaturalist.org/observations/231886526
https://www.inaturalist.org/observations/231882143
https://burkeherbarium.org/imagecollection/photo.php?Photo=wtu131196
