Lomatium Identification
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 .
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 (on the other hand I do not have a discriminating nose).
Cymopterus terebinthinus - except when fruiting looks a lot like a medium to large leafy yellow Lomatium with highly dissected shiny leaves. In WA state often found in dry sandy (sometimes rocky) soils and slightly sticky/shiny leaves and stems may have sand grains stuck on them. https://www.inaturalist.org/observations/154124936
L. ambiguum - yellow tall lanky glabrous Lomatium with highly divided leaves mostly on floral stem and looking somehow ill-formed with irregular sized rounded lobes (like moose antlers? https://www.inaturalist.org/observations/119621448). Flowers mid spring, no involucre or involucel (umbel bracts), umbels usually multiple and well separated when mature. https://www.inaturalist.org/observations/156334613 [unclear correct https://www.inaturalist.org/observations/156334613]
L. brandegeei - montane, medium to largish, deeply divided leaves, medium to narrow width leaflets with highly visible veination, yellow flowers, very common in developed serpentine soil in Wenatchees and more widely in Cascades despite being listed as vulnerable. https://www.inaturalist.org/observations/127119593 and https://www.inaturalist.org/observations/167719744
L. canbyi - often on shallow lithosol, small early flowering white with distinctive widish leaflets, usually glaucous/grayish/bluish and held close to flat, often quinate division, often with cusped leaflet tip. flower stems usually brownish red. https://www.inaturalist.org/observations/203170409 https://www.inaturalist.org/observations/154148039
L. columbianum - large and bushy rose flowers, unmistakable when in flower and even after, https://www.inaturalist.org/observations/149290580 and https://www.inaturalist.org/observations/149326711
L. cuspidatum - serpentine, distinctive leaves, https://www.inaturalist.org/journal/jhorthos/68301-lomatium-cuspidatum-non-technical
L. dissectum (Fernleaf) - large bushy, dark red or yellow flowers, wider leaflets than L. multifidum, https://www.inaturalist.org/observations/153198930
L. farinosum - often on shallow lithosol, very small yellow (or white) glabrous Lomatium with narrow branched leaves. Distinctive linear leaves with each side branch in three parts (biternate), folded V- to U-shaped cross-section, sometimes flattened out some when older. All the ones I have seen are on scabland. https://www.inaturalist.org/observations/200672186 (early) ; https://www.inaturalist.org/observations/201935288 (late)
L. geyeri - medium small, white flowers with fairly narrow leaflets, larger and more leaves than L. gormanii and usually growing in deeper soil. Has a distinctive double root bulge (https://burkeherbarium.org/imagecollection/taxon.php?Taxon=Lomatium%20geyeri). https://www.inaturalist.org/observations/200674165
L. gormanii - tiny white flowered glabrous, very early flowering, with no flower stem leaves (unlike piperi) https://www.inaturalist.org/observations/149332671
L. hallii - small to medium, yellow flowers, found in Oregon including Siskiyous, https://www.inaturalist.org/observations/152053418
L. howellii - uncommon, distinctive wide toothed leaflets, mostly on Klamath serpentine, https://www.inaturalist.org/observations/122515620
L. klickitatense - large puffy finely dissected, leaflets longer than L. papilioniferm, yellow flowers, https://www.inaturalist.org/observations/149327085 and https://www.inaturalist.org/observations/149328613
L. laevigatum - very narrow range mostly Columbia Transect, large yellow with long leaflets, involucel nearly absent, https://www.inaturalist.org/observations/154127684
L. leptocarpum (L. bicolor leptocarpum) - https://www.inaturalist.org/observations/122894913
L. linearifolium - very similar to L. gormanii, main obvious difference is elongated flower head.
L. lithosolamans - on shallow lithosol, uncommon, small white/purple early, usually with very few leaves that are V-shaped in cross section unlike other early salt and peppers. Endemic to Kittitas/Yakima Counties. https://www.inaturalist.org/observations/36510243
L. macrocarpum - often on shallow lithosol, medium sized, ground hugging when in flower (later more erect), green-white flowers with long white anthers (often yellow further south), hairy floral stalks and bracts, cusped leaflet tips, sometimes has quinate leaf division, ASYMMETRIC secondary umbel bracts (involucels) longer on outer hemisphere. https://www.inaturalist.org/observations/153200598
L. martindalei - montane, small, usually prostrate, wide leaflets, yellow flowers, https://www.inaturalist.org/observations/128448751
L. multifidum (Carrotleaf) - large bushy highly dissected leaf, dark red or yellow flowers, very similar to L. dissectum but narrower leaf segments, https://www.inaturalist.org/observations/155156511
L. nevadense - central to southern Oregon and further east and south, somewhat similar to canbyi.
L. nudicaule - sometimes montane, medium to large, unmistakeable broad leaves, yellow flowers, large swollen base where umbels branch, https://www.inaturalist.org/observations/117401560
L. papilioniferum - large showy yellow flowered, distinctive highly dissected leaves with short terminal leaflets, one of few on rock cliffs, extremely common in Columbia transect, https://www.inaturalist.org/observations/154112604
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 (https://www.inaturalist.org/photos/277673040), in marginal rocky sites. (convergent on or related to cuspidatum?) - https://www.inaturalist.org/observations/158648966
L. roneurum - distinctive leaves, narrow range on Chumstick and adjacent gneiss rocks, https://www.inaturalist.org/observations/155090697 https://www.inaturalist.org/observations/207315461
L. simplex - 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 stem leaves (unlike many triternatum). https://www.inaturalist.org/observations/154127265
L. triternatum - hard to distinguish from L. simplex. small to medium, yellow to pale yellow, narrow leaflets (narrowly lanceolate, except broader in var. brevifolium), dense short hairs on rachis and flower stem, sometimes has reduced leaf on flower stem (unlike simplex), sometimes disorganized looking leaves. https://www.inaturalist.org/observations/115265515
L. tuberosum - on coarse basalt scree/talus, rare adorable plant, very distinctive terete foliage, https://www.inaturalist.org/observations/154108537, fruits at https://www.inaturalist.org/observations/115128062
L. utriculatum - small lowland coastal, yellow flowers early spring, https://www.inaturalist.org/observations/152889731 and https://www.inaturalist.org/observations/200238973 for umbel details.
