Butterfly Plant Comments

Swallowtails

Papilio polyxenes coloro Thamnosma montana (Rutaceae) The host, Turpentine Broom, is common along the trail and the butterfly is a regular here.
Papilio eurymedon Possibly Prunus ilicifolia (Rosaceae), and/or Fraxinus velutina (Oleaceae) - Arizona ash tree. The largest butterfly on the trail, with a powerful flight.
Heraclides rumiko A citrus feeder, but I don't believe this is breeding on trail. I saw one fly by in the spring of 2020. No doubt a stray.

Pierids

Pontia beckerii I've seen females oviposit on Sisymbrium orientale and Descurainea pinnata here; there is no bladderpod, Peritoma arborea (Capparaceae), on this trail. Not uncommon in the spring. May use other mustards as well.
Pontia protodice They use a variety of mustards (Brassicaceae). Probably Descurainia pinnata ssp. glabra, as one that appeared to be ovipositing 4/5/15. Sisymbrium orientale also a good candidate.
Pontia s. sisymbrii Descurainea pinnata ssp. glabra Early flyer. Found a larva on this plant in late April, 2017, and adults in March that year and the next. Common in April, 2019.
Anthocharis s. sara I've seen the larvae on Descurainia pinnata ssp. glabra (Brassicaceae) not far from the trailhead. Watched one oviposit on Thysanocarpus laciniatus (narrow leaved lacepod) as well (4/23/17), and found several larvae on lacepod in April 2019. These typically fly from February into May, peaking Mar/April. In 2016, the Descurainia was senescent by mid-May, and the flight was nearly over.
Anthocharis c. cethura Mustards, but time will tell which. First and only sightings by me were in early April, 2019.
Anthocharis lanceolata desertolimbus Boechera perennans (Brassicaceae) This is a great trail to see this recently-described butterfly. My sightings have been late March and early April, usually with the adult taking nectar on Acmispon rigidus.
Colias harfordii Mainly Astragalus (Fabaceae), but rarely Acmispon glaber Astragalus douglasii (not on the trail) is the classic host, but the Monroes also list A. palmeri, which is the most common of the three rattlepod species here.
Colias eurytheme Deerweed, rattlepod, poss. lupines. The Emmels (1973) have deerweed, and "possibly several Astragalus species". The Monroes list Astragalus crotalariae, Acmispon strigosus, A. glaber, and Lupinus bicolor. So there are many candidates on this trail.
Abeis nicippe Cassia sp. Saw one April 22, 2017. I think this was my only sighting of this butterfly on this particular trail to date. But not too surprising.
Zerene eurydice Amorpha fruticosa (Fabaceae), a common plant on this trail. The abundant host, especially at drainages along the trail, is the reason there are so many of these flying here practically all year.
Zerene c. cesonia Amorpha fruticosa (Fabaceae) mostly. Not at all common, but apparently on the trail. This species hybridizes with eurydice, and I've seen the yellow female with dark dorsal markings, just to confuse things. But I'm reasonably sure it is on the trail and Gordon Pratt sees it regularly in Anza.
Nathalis iole Many hosts. On this trail, probably Adenophyllum porophylloides (Asteraceae)(San Felipe Dyssodia). A very common butterfly most of the year. This is a beautiful, tiny sulphur with darker and lighter seasonal forms. Often patrols the trial, stopping on the dirt regularly. The Monroe's Anza-Borrego book has three hosts: San Felipe Dyssodia, Spanish Needles (Palafoxia arida), and Cinchweed (Pectis papposa). The latter two are not on the Chester list. I've searched in vain for larvae on the Dyssodia so far.

Hairstreaks and Blues

Atlides halesus corcorani Uses mistletoe (Viscaceae), and there are three here: Phordendron villosum, densum and califoricum, with the first two common on juniper and ceanothus. Found an egg on densum on juniper on May 27, 2016. Not easily seen here, but it is present. An absolutely stunning large hairstreak with neon-like colors set against black. Always a treat to see, especially when fresh.
Callophrys augustinus iroides Many hosts; I've recently seen them on Rhus ovata but they probably use Ceanothus perplexans (Rhamnaceae) as host here. Not as common here as they can be elsewhere. A spring flyer.
Callophrys dumetorum perplexa Many, inc. buckwheats, deerweed, Ceanothus. They can be fairly common earlier in the spring around patches of Eriogonum fasciculatum not far from the trailhead parking area.
Callophrys loki Juniperus californica (Cupressaceae) is a dominant plant here. A featured flyer on this trail, it can be found conveniently right at the parking lot among the junipers to the north, as well as along the trail wherever there are junipers. The colors of this population on the ventral side can vary a bit, but typically (when fresh) they have plenty of blue and/or pink, while subspecies juniperaria, on the desert side of the San Gabriels, has more olive green. That said, I saw a very green one this spring (2016).
Satyrium c. californica An Oak and Ceanothus feeder. Early summer flyer.
Satyrium auretorum spadix Oaks Also early summer as an adult.
Satyrium saepium chalcis Probably Ceanothus perplexans (Rhamnaceae) More common along the Santa Rosa Truck Trail a few miles to the west, but also usually present here if not common.
Satyrium tetra Cercocarpus betuloides var. betuloides (Rosaceae) I've seen these in June and July along the Santa Rosa Truck Trail, but the host also is present on Cactus Spring Trail.
Strymon istapa clenchi Hibiscus denudatus (Malvaceae), which isn't on the trail. Uncommon, but flying late March, 2014 and early April 2015.
Strymon melinus pudicus Too many to list, but California Buckwheat is one. Not surprising to find them anywhere.
Leptotes marina Several hosts, including Senegalia greggii and Amorpha fruticosa (Fabaceae), and I see it commonly around these. A common garden butterfly that also thrives in the desert.
Brephidium exilis One expects saltbush, but no Atriplex grows on this trail. Instead, it may use Salsola tragus (Chenopodiaceae) and/or Amaranthus albus (Amaranthaceae). Uncommon here, but this handsome and diminutive butterfly may appear almost any time of the year on the trail. Not sure it breeds here, but it's possible. I have an April record and a few from autumn.
Celastrina e. echo Uses many common trees and shrubs, inc. Ceanothus, Oaks. I have only a couple of confirmed sightings of this butterfly here: in late April and May of 2017.
Glaucopsyche lygdamis australis I've seen one oviposit on Acmispon rigidus (3/24/12), and it no doubt uses deerweed - A. glaber (Fabaceae) on this trail. Both are common right from the trailhead. An early spring flyer which can be common some years.
Philotes s. sonorensis Host here must be Dudleya saxosa ssp. aloides (Crassulaceae) Another stunning and sought-after butterfly that can be found here in the spring, though perhaps not reliably. My records are from early March through April.
Euphilotes b. bernardino Eriogonum fasciculatum (Polygonaceae) Common butterfly that uses a common host. A spring flyer that can become abundant some years.
Euphilotes dammersi dammersi Eriogonum wrightii vars membranaceum and nodosum (Polygonaceae) Fall only around the host buckwheat, which blooms at that time. Pratt and Emmel (1998, p.211) divide dammersi into three populations, one of which is a low desert group extending from the San Bernardino Mountains south into Mexico. (There is also a spring-flyer on the northeast side of the San Bernardinos on E. kennedyi or E. davidsonii, and a population in the Mojave.) A good place to see this blue in autumn is to check the patches of wrightii two-tenths of a mile from the trailhead, just before the trail signs at the road junction. Another is just short of the creek before the so-called "dolomite mine". The black spots on the underside have a characteristic "smudging" that is easy to see.
Hemiargus ceraunus gyas Senegalia greggii, Prosopis glandulosa and locoweeds such as Astragalus palmeri (Fabaceae). I saw a female ovipositing on Senegalia greggii buds on May 27, 2016.
Plebejus a. acmon Many in several families Found a larva on Eriogonum davidsonii on May 27, 2016.
Plebejus m. monticola Eriogonum fasciculatum (Polygonaceae) This and the above taxon are part of an interesting complex. Both fly on this trail. I label many of them "acmon complex" if it isn't clear what's what. John Emmel considers monticola a full species (separate from lupini) and says they are "atypical" in this area.

Metalmarks

Calephelis wrighti Bebbia juncea (Asteraceae) Not common at all here
Apodemia v. virgulti Eriogonum fasciculatum (Polygonaceae) Common and multiple brooded, so may be found from spring to autumn. On this trail, there is phenotypic variety. Some males have little orange on the hind wing. Females are a noticably lighter color and larger than the males, some more than others.

Nymphalids

Danaus plexippus Milkweed, but probably doesn't breed here. See next entry. Occasional migrant
Danaus gilippus thersippus Funastrum crispum (Wavyleaf twinevine) has been found at Pinyon Flat, and also on the right at the small drainage just before one comes to Sawmill Road (but I haven't found any); it is in the Asclepiadaceae, as is Matelea parvifolia (Spearleaf), which was found a tenth of a mile shy of Horsethief Creek. I'm not sure whether this is used by Queens and/or Monarchs locally. A desert butterfly sometimes seen taking nectar here as at Horsethief Creek on the goldenrod.
Chlosyne acastus neumoegeni Acamptopappus sphaerocephalus (goldenhead) Two seen patrolling approx. 2 miles down the trail on March 3, 2020. I'd never encountered this butterfly here before this year.
Chlosyne leanira wrighti Castilleja foliolosa (Scrophulariaceae) Late spring flyer that may have a fall brood if conditions are right (saw one Sept. 20, 2014 after not seeing them that spring). I've seen larvae in mid-April as flight began, with adults through May. They are usually well down the trail where the host is more common. But this striking butterfly may be - or seem to be - absent many years. I first saw them in Spring 2011 here, and they were easily found the next spring as well. Since then, I've had a single fall 2014 sighting. In 2016, I saw neither a larva nor an adult, though the plants were healthy at the usual locations.
Chlosyne californica Bahiopsis parishii (Asteraceae) Tom Chester's plant guide has the host beginning at 2.37 miles from the trailhead. The population of this butterfly seems to fluctuate, but it can be fairly common at Horsethief Creek some years on the Goldenrod there, and individuals can show up anywhere. In 2017, I was seeing it even in town in Palm Desert.
Junonia grisea I thought it was a stray, but I saw one ovipositing on Cordylanthus rigidus ssp. setiger on June 7, 2020 down the trail. Also on the trail is Plantago patagonica, or perhaps the local paintbrush spp. A brief sighting on June 3, 2017, and the one mentioned ovipositing three years later almost to the day.
Dymasia dymas imperialis The host, Justicia californica (Acanthaceae), isn't on the trail. I saw one September 20, 2013, and another April 5, 2015, but this trail is (probably) quite a ways from where the host Chuperosa is known to grow (online records have it several miles to the north and east). So add this to the list of unexpected sightings.
Phyciodes m. mylitta Various thistles, monkeyflower, others, but not established here apparently. I've seen many larvae on thistles in the San Jacintos. A single sighting for me on this trail: May 18, 2012. Can be common elsewhere.
Euphydryas chalcedona nr hennei Keckiella antirrhinoides var. microphylla (Plantaginaceae) confirmed on this trail. True hennei is from Anza-Borrego, and the chalcedona here tends to be lighter, possibly due to gene flow with corralensis to the north. Common, sometimes abundant, with a fall flight some years, possibly most. I was surprised to see one on November 29th, 2022, a very late date. These will, at times, be your regular companion on a hike all the way down the trail to Horsethief Creek, where they congregate on Goldenrod if it's in bloom. The larvae can be found easily on the yellow-flowered host, with early instars in nests until the plant begins to dry out in the early summer. They go to ground (where they are not easy to find), and resume feeding when the plants are again edible, as after summer/fall rains or in the spring.
Vanessa cardui Too many to list. Probably just passing through for the most part.
Limenitis lorquini powelli Willows (Salicaceae). This trail has Salix exigua, laevigata, and lasiolepis. Males patrol some of the places down the trail where willows grow.
Adelpha californica Three oaks are listed in Chester's plant guide: Quercus cornelius-mulleri; Q. wislizeni var. frutescens; and Q. acutidens (Fagaceae). Of the three, only Q. wislizeni is listed as a host for californica in my various books. Can be common on the trail, particularly in tree-lined canyons. Quercus wislizeni var. frutescens first appears on the trail near the junked car at the "Dolomite Mine". Overwinters as a larva.
Nymphalis c. californica Ceanothus perplexans most likely. I hadn't really noticed this one before the spring of 2017 (late April), but they can become a regular part of the mix before numbers fall off again. Ceanothus perplexans - cupped-leaf ceanothus - is the likely food plant on this trail, but it doesn't seem to be a preferred host. It uses leucodermis in the Keen Camp Summit area.

Skippers

Epargyreus clarus californicus Probably Amorpha fruticosa (Fabaceae) here. Uncommon, but sometimes seen well down the trail, inc. at Horsethief Creek.
Thorybes phylades indistinctus Amorpha fruticosa, possibly others in the Fabaceae family. Not common here.
Pholisora c. catullus Chenopodium fremontii; Amaranthus species albus, fimbriatus, palmeri, torreyi; Ambrosia acanthicarpa (bur ragweed) possible here. May 12, 2018 is the only time I've encountered one here.
Systasea zampa I found larvae Oct. 18, 2015 on Abutilon palmeri (Malvaceae) at Moeller’s nursery in Palm Desert; but that's not on the trail. A rare sighting here, but it turned up March 26, 2016, and since then a few times in the fall, most recently in October, 2019.
Erynnis brizo lacustra Quercus cornelius-mulleri (Fagaceae) The host is plentiful, but this butterfly can be scarce. I haven't seen it the last few years. I watched it oviposit once on the host oak shrub, so it may at least be an occassional resident. Can be common some years in the San Jacintos.
Erynnis funeralis Probably Acmispon glaber and/or A. rigidus (Fabaceae). A regular. Males may patrol areas inexhaustibly.
Erynnis t. tristis Oaks Gordon Pratt says these can't be separated from funeralis without genital dissection. I assume some of the duskywings with white fringe on the hind wings are these as there is abundant oak here.
Erynnis propertius Oaks, which on this trail means either Quercus cornelius-mulleri, which is relatively common here; Q. acutidens, which is uncommon; and Q. wislizeni var. frutescens, even rarer. Saw one on June 7, 2020 taking nectar on Eriogonum fasciculatum; that's my only sighting of this species on this trail. There is a June 9, 2019 record for the Santa Rosa truck trail on iNaturalist.
Erynnis afranius Acmispon americanus (Fabaceae) - check after first “creek”. Noticably smaller than funeralis, and with hyaline spots, unlike brizo. E. pacuvius may fly here as well.
Pyrgus scriptura apertorum Sphaeralcea ambigua (Malvaceae). Another small but sought-after butterfly. A fairly reliable spot on the trail is at the Sawmill Rd. junction just to the north, where the host is common and males patrol. Larvae make a silk shelter atop a leaf and place spicules in it to disguise their feeding area. They prefer low-growing mallow plants acc. to Gordon Pratt.
Burnsius albescens Sphaeralcea ambigua (Malvaceae). Fairly common around the host at times. This and the following species fold and silken a leaf shut as larvae. Opening these may reveal one of the two; ericetorum have hairier heads.
Heliopetes ericetorum Sphaeralcea ambigua (Malvaceae). This plant - I like Apricot Mallow as the common name - does very well on this trail. The flowers are a very attractive shade of orange. The rose-colored variety grows to the north down the highway. Becomes common as spring turns to summer, esp. around patches of the host. In late summer they can be very common. There are three white skippers in the mallow patches here.
Copaeodes aurantiaca Cynodon dactylon (Poaceae). Multiple broods.
Hesperia juba Bromus madritensis ssp. rubens (Poaceae). More common in spring, but does fly late summer into fall as well.
Agathymus stephensi Agave deserti (Agavaceae). Always great to see these powerful flyers. Larvae burrow into the roots of the host, which is plentiful on this trail. Stephensi flies ca. September-October. Can sometimes be found zipping around the hosts on the first leg of the trail not far from the trailhead, and at various places further down trail. A good flight in October 2019.