Great Basin Naturalist

Volume 37 | Number 4 Article 4

12-31-1977 The alpine of aC stle Peak, Nevada County, Arthur M. Shapiro University of California, Davis

Follow this and additional works at: https://scholarsarchive.byu.edu/gbn

Recommended Citation Shapiro, Arthur M. (1977) "The alpine butterflies of , Nevada County, California," Great Basin Naturalist: Vol. 37 : No. 4 , Article 4. Available at: https://scholarsarchive.byu.edu/gbn/vol37/iss4/4

This Article is brought to you for free and open access by the Western North American Naturalist Publications at BYU ScholarsArchive. It has been accepted for inclusion in Great Basin Naturalist by an authorized editor of BYU ScholarsArchive. For more information, please contact [email protected], [email protected]. THE ALPINE BUTTERFLIES OF CASTLE PEAK, NEVADA COUNTY, CALIFORNIA

Arthur M. Shapiro'

.-Vbstract.— The west slope of Basin and Castle peaks and the ridge between them displays a wind-generated tree line below 8500 ft, with dry alpine fell-field vegetation above. The fauna, although depauperate compared to that of the High Sierra farther south, includes some truly boreal elements such as Oeneis ivallda,

Pleheius shasta, and Hesperia nevada. These species commonly occur 1500 to 4000 ft higher in the southern Sierra.

The of California is about (11,429 ft), again because of its 360 miles long, from the Lassen Peak area proximity to a road. Lepidopterists have in the north to Walker Pass in the south. visited other alpine areas including some to Along the crest the summits become pro- the north, but have not reported on their gressively higher southward—from 6000- findings. Although Castle Peak (long known 8000 ft in Plumas and Sierra counties to as Stanford Peak or Mt. Stanford) has been

10,000 ft west of , 13,000 ft in collected by botanists for over a century, I , and 14,000 ft near can find no record of its having been in- . The term "High Sierra" is vestigated for butterflies before 1972. This properly applied to the region from slightly is surprising, since it is an easy day's hike north of Yosemite to Cottonwood Pass. This from Interstate Highway 80 (formerly U.S. area, averaging 20 miles wide over its 150- 40); perhaps the forbidding south face of mile length, includes about 90 percent of the mountain, which gives it its name, has the Arctic-Alpine life zone in California. given it a more difficult reputation than it

Tree line drops below 10,000 ft from Pyra- deserves (Fig. 1). Again, it has not been mid Peak northward, reaching about 9000 ft widely recognized that an alpine fell-field on the north side of Lassen Peak (where it was present on this mountain; True (1973) is ill-defined due to the rocky substrate), but states that the Arctic-Alpine life zone does there are few areas of alpine vegetation in not occur in Nevada County. This is a mat- the northern Sierra, and they have not been ter of interpretation, since so many organ- well studied by biologists. The most exten- isms are distributed as if it does. The vege- sive of them south of Lassen Peak is on the tation, as described below, demonstrates west side of the andesitic mass forming Ba- that the summit community is easily consid- sin Peak (9015 ft). Castle Peak (9103 ft), ered an alpine fell-field, and not even a and the ridge connecting them. Castle Peak very depauperate one. Smith (1973) notes is the second highest in Nevada County and that around Lake Tahoe "scarcely any of in the Sierras proper, north of . the lower peaks between 8500 and 9500 ft The Sierran Arctic-Alpine butterfly fauna are forested at their summits and these sup- is best known around (9941 ft), port an illusion if not, in fact, the actual where fell-fields are readily accessible in a plant associations of summit screes and al- day's hike from a good road. Tilden (1958) pine fell-fields." and Garth and Tilden (1963) have reported The Alpine Vegetation in detail on its composition and ecological characteristics. Another fairly well-known, Tree line is developed only on the west though unpublished, alpine fauna is that of side and is obviously related to the pre-

Department of Zoology, University of California, Davis, California 9561(:

443 444 GREAT BASIN NATURALIST Vol. 37, No. 4

vailing westerly wind. This was noted as pressure gradient across Donner Pass, and early as 1921 by Smiley (p. 57). No mete- its location overlooking the great canyon of orological data are available for Castle the South predispose it to high

Peak, but its orientation and elevation far winds. In my experience it is a very unusual above the surrounding terrain, the persistent day when the midaftemoon wind on the

'" ' 4^-- '-1., - -t*^

Fig. 1. Southwest face of Castle Peak seen from near Castle Pass, showing eroded "badlands" and unvegetated talus. This is the aspect of the mountain visible from the highway.

Fig. 2. Trees along the jeep trail below Basin Peak, showing shaping by prevailing westerly wind at about 8000 ft.

Fig. .3. Upper edge of subalpine forest belt, showing krwnmhoh of lodgepole pine and mountain hemlock be- low the ridge top south of Basin Peak.

Fig. 4. Tree line is clearly visible on the west side below the ridge; note "crawling tree." Photographed from near summit of Basin Peak. Dec. 1977 SHAPIRO: ALPINE BUTTERFLIES 445

ridge top is less than 20 mph. The trees of vascular plants collected by True (1973) show abundant evidence of battering by the and myself have been categorized by the west wind (Figs. 2-4). Matted krwnmholz, plant communities in which they are re- consisting of Pinus murrayana Grev. & corded by Munz (1970). The boreal charac- Balf., P. albicaulis Engelm., and especially ter of the vegetation emerges clearly from Tsuga mertensiana (Doug.) Carr., occurs as these statistics. Although only 18 plant spe-

much as 350 ft below the ridge top on the cies are shown as being of east-slope distri- west side, and farther down the tops of the bution, the Castle Peak alpine fell-field (like trees are commonly bent to the east. On the many in the High Sierra) shows a marked east side erect, pyramidal trees come almost east-slope aspect, accentuated by the con- up to the ridge top. A few nearly prostrate spicuousness of Artetnisia and Purshia.

trees occur at low points along the ridge, Much of the alpine flora of the Sierra is be- and one large individual (known locally as lieved to be evolutionarily derived from the

the "crawling tree") is pressed almost flat high desert (Chabot and Billings 1972). Af- against a 45 degree slope just below the ter snowmelt the thin, porous alpine soil crest. dries out rapidly; occasional air-mass thun-

The extensive treeless area which I am derstorms in summer temporarily replenish calling a fell-field (Figs. 5-8) includes about surface moisture. Such thunderstorms are 100 species of vascular plants. Seventy of rather more frequent on Castle Peak than these are listed as alpine fell-field in- in the surrounding area, presumably because habitants by Munz (1970) and five are listed its greater elevation promotes the growth of only from that community. Of the 24 "in- cumulus. dicator" plants listed for alpine fell-fields by I have collected the Basin-Castle peaks Mimz (1970: 10-18), 6 occur on Basin and area 13 times from 1972 through 1977. The Castle peaks. Smiley (1921) lists some addi- entire area above tree line was collected on tional alpine "indicators" which occur on two dates: 28 July 1976 and 8 July 1977. Basin-Castle peaks. The alpine flora in- The general Donner Pass region has been cludes the following distinctive taxa: Arte- visited over 100 times since 1972. misia tripartita Rydb., A. arbuscula Nutt., Railardella argentea (Gray) Gray, Hap- The Butterfly Fauna lopappus macronenia Gray, Castilleja am- Family Satyridae higua Jones, C. lemmonii Gray, Polemoniiim pulcherrimimi Hook., Oeneis ivallda (Mead).— The most charac- Gray, Primula suffrutescens Gray, Cassiope teristic Sierran alpine butterfly, ivallda oc- mertensiana (Bong.) D. Don., Epilobium oh- curs from about 7000 ft in the east end of cordatum Gray, E. anagallidifoUum Lam., Donner Pass (presumably as a stray) to Linum lewisii Pursh., Lupinus lohbii Gray, 14,000 ft in the southern Sierra. Breeding Astragalus whitneyi Gray, A. austinae GraLy, A. bolanderi Gray, Ivesia gordonii (Hook.) Table L Occurrence of the 232 plant species re- T. & G., Potentilla drummondii ssp. Bruceae corded from Basin-Castle peaks by plant communities (Rydb.) Keck, Sibbaldia procumbens L., Pur- recognized in the Sierra Nevada by Munz (1970). The shia tridentata (Pursh.) DC, Saxifraga apri- mean number of categories (not communities) per spe- cies is 2.65. ca Greene, S. bryophora Gray, Draba crassi- folia Grah., D. densifolia Nutt., Erysimum perenne (Wats.) Abr., Ranunculus eschs- choltzii var. oxynotus (Gray) Jeps., Silene sargentii Wats., Lewisia pygmaea (Gray) Rob., Oxyria digyna (L.) Hill, Eriogonum ovalifolium var. nivale (Canby) Jones, Salix anglorum var. antiplasti Schneid., Carex hel- leri Mkze., etc. In Table 1 the 232 species No. 4 446 GREAT BASIN NATURALIST Vol. 37,

ft) a few colonies exist about 8000 ft on Mt. Judah pine summit of Mt. Lola (9143 and Anderson Peak in Donner Pass south of miles to the north. Oeneis ivallda was ex- Interstate 80, but the one on Basin-Castle is tremely abundant all along the crest on 8 the only colony known north of that road. July 1977, with 250 to 300 individuals seen. There may be a colony on the smaller al- It was most numerous in the alpine sage-

, ^^^ luf^^^"*'' ^^'

^^.. •<**' .at It .

grasses, Eriogonwn species, Fig. 5. Habitat of Oeneis ivallda just below summit of Basin Peak; turf of sedges, and Astragalus whitneyi. composites below Basm Fig. 6. Habitat of Oeneis ivallda and Hesperia nevada in alpine sagebrush, grasses, and Peak. Large-leaved plant foreground is Fig. 7. Ridge top showing trees on east side and alpine vegetation on west. m Wyethia mollis (Compositae). tree line. Fig. 8. Ridge top looking northwest from Castle Peak, showing extent of area above Dec. 1977 SHAPIRO: ALPINE BUTTERFLIES 447 brush areas and around isolated rock out- Springs, Sidalcea glaucescens Greene (Mal- crops. It is said to have a two-year Hfe vaceae), occurs on Basin Peak. cycle and to be absent in many colonies in even-numbered years, but it was taken on Family Lycaenidae

Castle Peak in 1976. Variation is marked, Satyrium especially in males. The host plant is un- fuUginosum (Edwards).— Com- known; 49 species of grasses and sedges are mon all along the ridge top, second half of July. The butterflies scarcely fly at all un- known from its habitat here. less disturbed, Cercijonis oetus (Boisduval).— An east- and they may be seen walk- ing on Eriogoniim and yellow composite slope element, this small brown Satyrid is flowers on windy afternoons. common long after Oe. ivallda in the same Four species of lupines occur I places, flying mostly in August and on into on the summit, but have been unable to early September after most other species establish an association. Callophrys lemberti Tilden.— Frequent, have disappeared. It is presumably a grass to feeder. mid-June mid-July, among Eriogonum plants and, like the last species, seldom seen

Family Nymphalidae flying. The host is presumably an Eriogo- num; eight taxa are recorded here. Speijeria egleis (Behr).— Males are abun- Lycaena nivalis (Bdv.).— Occasional on dant hilltoppers along the crest in July and the ridge top among the Eriogonum or on August, but no females have been collected. composites, but less common than in the This is the only silver-spotted fritillary seen subalpine areas along the trail to Castle in the alpine fell-fields, which are too dry Pass. Late June to early August. for S. morrnonia arge (Strecker). Lycaena heteronea Bdv.— Frequent in Phyciodes campestris montana Behr.— Oc- "rock gardens," second half of July, presum- casional, June to August, but not known to ably feeding on an Eriogonum. Females are breed. Much more common on dry or moist quite dusky. slopes in the lower subalpine areas. Everes amyntula (Bdv.).— In the northern Pohjgonia zephyrus (Edwards).— In- Sierra and the Trinity Alps occurs a sub- frequent; worn specimens of both sexes (hi- alpine-alpine amyntula which is larger and bernators) on the crest in July. Breeding duller than the montane coniferous forest status unknown. This is a very common, populations associated with native Vicia and widespread species around Donner Pass. Lathyrus at 1000 to 5000 ft. This ,

Nymphalis californica (Bdv.).— Occasion- which occurs at 7500 ft in Trinity County al, especially in migration years. There are and above 8500 ft in the Donner Pass area no Ceanothus (Rhamnaceae) on the ridge (Mt. Judah, Anderson Peak, Basin-Castle) is top, but several species used by this associated with Astragalus whitneyi Gray occur in subalpine areas below. (Leguminosae) and oviposits in the in- Nymphalis milberti (Godart).— Three seen florescences. Like other lycaenids on Castle (one taken) on the ridge top, apparently Peak, these seldom fly and may hilltopping, 8 July 1977. The host plants have to be scared up from the plants. They {Urtica spp.) do not occur above tree line. occasionally visit flowering Eriogonum. A female found on Basin Peak, 9 August Everes amyntula is done flying before 1977. Plebeius shasta (Edw.) begins flying in the

Vanessa virginiensis (Dniry).— Occasional, same places; its peak flight is in early July. July to September. Three potential host Philotes enoptes (Bdv.).— A single aberrant plants are recorded, but no larvae have male was taken on 8 July 1977 along the been found. ridge top. It was not associated with an

Vanessa annabella (Field).— Occasional, Eriogonum. This species is so sedentary that July to August. A female was taken on 8 a breeding colony must be assumed to exist. July 1977, and the usual host plant at Soda Celastrina argiolus echo (Edw.).— Occa- 448 GREAT BASIN NATURALIST Vol. 37, No. 4

Fig. 9. Characteristic alpine butterflies from Castle Peak area: a, b, light and dark male Oeneis ivallda; c, fe-

male Oe. ivallda; d, male Hesperia nevada; e, female Satyriwn fuliginosum; f, g, Plebeius shasta male and female;

h, i, Pieris occidentalis male and female. Dec. 1977 SHAPIRO: ALPINE BUTTERFLIES 449

sional, June to mid-July, both sexes. Breed- females are not uncommon. Very variable. ing status uncertain. Much commoner in the Eggs and larvae have been collected on the subalpine zone lower on the mountain, following Cruciferae: Arabis holboelli Horn, where its hosts (especially Ceanothus) are vars. pinetorum (Tids.) Roll, and retwfracta common. (Grah.) Rydb., A. platyspemia Gray, Descu- Plebeius saepiolus Bdv.— Occasional, July. rainiu richardsonii ssp. viscosa (Rydb.) Detl., Two clovers {Trifolium monanthum Gray, and Draba crassifolia Grah. This is the only T. productum Greene) occur on Castle resident butterfly on Castle Peak that may

Peak. This is one of the most common spe- be partially double-brooded (some years). cies in the meadow at Castle Valley. (Note: P. protodice Bdv. & LeC. has not Plebeius icarioides (Bdv.).— Common been seen on Castle Peak but was recorded tliroughout July. On the ridge associated in the subalpine zone in 1972 and again in with Lupinus arhustus Dough, ssp. silvicola 1977.) (Hell.) D. Dunn. Anthocaris sara Stella Edwards.— Occa- Plebeius shasta (Edw.).— Like Oeneis sional as a hilltopper, males only seen; ivallda, this is a characteristic Sierran alpine breeding status uncertain. Here, as in Don- butterfly. It is incredibly abundant from ner Pass (Emmel and Emmel 1962, Shapiro, mid-July through mid-August, and very var- unpublished), occasional white males in- iable, although consistently larger than ma- distinguishable from A. s. sara Lucas are terial from Inyo and Mono counties. It found. Eastward and lower, at Truckee, oviposits on pedicels of Astragalus whitneiji only the yellow form occurs. This situation Gray, often on the same plants on which E. deserves further attention. amyntula laid three weeks before. Euchloe ausonides Lucas.— One male, 8 Plebeius acmon (Westw. & Hew.).— This July 1977 on the ridge top. This small race ubiquitous, weedy species occurs as a stray of ausonides is about the same size as the and may breed occasionally, but does not next species, flies with and a bit after it, overwinter. Recorded from July to Septem- and is commonly confvised with it. I have it ber. from the Trinity Alps to Eldorado County,

Plebeius lupini (Bdv.).— Common in "rock 5000 to 9000 ft. It may be recognized by gardens," where it is associated with Eriogo- the thinner bar at the end of the forewing num umbellatwn var. covillei (Small) Munz cell; somewhat duller white color; less in- & Reveal, which is also the host plant in tense green mottling below; and more angu- Donner Pass. Late June to mid-July. lar hindwing. It seems always to be rare. Glaucopsyche lygdamus behrii (Edw.).— Euchloe hyantis (Edw.).— A common hill- Resident but not common, late June to topper, mid-June to mid-July. It is not un- early July. Associated with Lupinus pohj- common to find hyantis, sisymbrii, and occi- phyllus Lindl. ssp. superbus (Hell.) Munz. in dentalis flying together around the same a seep area on Basin Peak. rocky crag on Castle Peak.

Family Family Papilionidae

Colias eurytheme Bdv.— A common flyup, Papilio zelicaon Lucas.— Common. Males perhaps breeding but never overwintering; hilltop, and females are occasionally en- all season. countered (especially on the ridge from Pieris sisymbrii Bdv.— Frequent, late June Castle Pass to Castle Peak). Late June to to mid-July. Males hilltopping; females not early August. Host plant unknown; presum- seen, and breeding status uncertain; females ably one or more of the six recorded Um- have been collected in Donner Pass. bellifers. Pieris occidentalis Reakirt.— The most Papilio indra Reakirt.— Frequent. Males common butterfly on the ridge top, flying hilltop, and females are occasionally seen on mid-June to September. Males hilltop, but the crest and also on the ridge to Castle 450 GREAT BASIN NATURALIST Vol. 37, No. 4

Fig. 10. Characteristic alpine butterflies from Castle Peak area: a, male Papilio zelicaon; b, female Papilio in-

dra; c, male Pieris sistjinbrii; d, male Euchloe ausonides; e, female Nyrnphalis milberti; f, g, Everes amijntula male

and female; h, female Lycaena heteronea; i, male Polites sahtdeti tecumseh. Dec. 1977 SHAPIRO: ALPINE BUTTERFLIES 451

Pass. Late June to mid-July. Oviposition ob- meadows above tree line. He records 43 served on Loynatiiim dissectum var. midti- species, as against 40 in the present study; 5 fidiim (Nutt.) Math. & Const. are alpine obligates, as against 3 at Castle Papilio eunjmedon Lucas.— Occasional Peak. Missing at Castle Peak are the alpine male hilltopper, July; the host plants do not species Chlosyne damoetas malcolmi (Com- occur above tree line. stock), behrii (Edwards), and Hesperia Parnassius clodius baldur Edwards.— Oc- miriamae MacNeill. All of these are High casional, both sexes, July, probably flyups Sierran endemics unrecorded north of Yose- from the subalpine area where it is quite mite. common. Some species found at Tioga Pass above tree line are strictly subalpine species far- Family Hesperiidae ther north around Donner Pass. These in- clude Speyeria mortnonia arge (Strecker), Hesperia juba (Scudder).- Occasional, Lycaena editha (Mead), L. mariposa Reakirt, June and September; breeding status un- L. cupreus (Edwards), and Agriades glandon known. A very widespread species around podarce (Felder and Felder). One species, Donner Pass. Lycaena rubidiis (Behr), is a common mem- Hesperia )mrpalus ijosemite Leussler.— ber of the alpine fauna at Sonora Peak, oc- Only male hilltoppers thus far recorded, curs in Donner Pass, and may yet turn up second half of July, occasional. at Castle Peak where at least one of its Hesperia nevada (Scudder).— Occasional known hosts, Oxyria digyna (L.) Hill (Poly- on the ridge top and crags, both sexes, first gonaceae), occurs (see Johnson and Balogh, half of July. This very dark, small, shaggy 1977). It is basically an east-slope animal. skipper is a true alpine species in the Don- Another species found on Sonora Peak but ner Pass region. The Emmels (1962) found imrecorded at either Tioga Pass or Castle it on the summit of Mt. Judah (8243 ft). Peak is the "alpine" member of the Plebeius Polites sabideti teciimseh (Grinnell).— In- melissa (Edwards) complex. At Sonora Peak frequent, grassy area below ridge top, first and also on Gumboot Butte, far to the half of July. Much more common in the north in the Trinity Divide, it occurs on As- subalpine meadows, where it oviposits on tragalus ivhitneyi Gray, which is one of the Agrostis scabra Willd. and perhaps other most common plants on the Basin-Castle grasses. ridge top. Farther northwest, on Packer's Pyrgus communis (Grote).— Common, first Peak in the Trinity Alps, it is replaced on half of July, ovipositing on Sidalcea glauces- this plant by an ecotype of P. argyrognomon cens Greene (Malvaceae). anna (Edwards), but in the Donner Pass re- Pyrgus niralis (Bdv.).— Infrequent; grassy gion this insect occurs in subalpine marshy open places on the ridge mid-June to early habitats on Lupinus polyphyUus Lindl. and July. Host plant unknown. has never been found at Castle Peak or on Erynnis propertius (Scud. & Burg.) — Oc- Astragalus. Plebeius melissa is pre- casional hilltopper, males only. July. Com- dominantly an east-slope species. Multi- mon in subalpine areas. voltine "Great Basin" melissa has been Thorybes nevada Scudder.— Occasional on found in Donner Pass (Shapiro, unpub- the ridge as a hilltopper, probably not lished). Another east-slope species, Satyrium breeding; late June to mid-July. Abundant behrii (Edw.), which occurs at Truckee and in Round and Castle valleys. Donner Pass, has not been found on Basin- Castle although its host, Purshia, is common Comparisons to Tioga Pass there; it is not usually an alpine butterfly in Tilden's Tioga Pass study area is much the northern Sierra. more ecologically diverse than Basin-Castle The Donner Pass fauna as a whole is Peak. It incTudes a spread of over 3000 ft in about 70 to 75 percent univoltine. Tilden elevation, moraines, boggy areas, and wet claims that of the resident (as against colo- 452 GREAT BASIN NATURALIST Vol. 37, No. 4

nizing, nonwintering) tauna of Tioga Pass distributions, rather than a rigidly "zonal" only Polites sabuleti tecumseh is bivoltine, approach such as is commonly found in the but this claim is spurious (see Shapiro 1975). butterfly literature. At Castle Peak one breeding resident iPieris occidentalis) and one whose status is un- Acknowledgments known {Hesperia juba) appear bivoltine. Both are probably bivoltine at least in the Some of the data included here were ob- subalpine zone at Tioga Pass as well. Of the tained by Adrienne R. Shapiro, Frances remaining 38 species at Castle Peak, about Sharpies, Cheryl Palm, and Kenneth Ma- two-thirds are "early" season emergents suda. Help was also received from Dr. E.

(e.g., Oeneis ivallda, Everes arnyntula, Hes- W. Jameson, Jr., Allen Allison, and Dr. Jack peria nevada), appearing about three to five Major. This research was partially sup- weeks after bare ground appears. The re- ported by grant D-804 from the Committee maining third are "late" {Plebeius shasta, on Research, U.C. Davis. Lycaena heteronea, Cercyonis oetus). In the case of E. arnyntula and P. shasta, which Literature Cited have the same host plant, this seasonal dif- Chabot, B. F., and W. D. Billings. 1972. Origins and ference may facilitate coexistence. The ecology of the Sierran alpine flora and vegetation. flight season in a "normal" year is about Ecol. Monogr. 42: 163-199. 100 days, from late Jime to late September. Ecological Emmel, T. C, and J. F. Emmel. 1962. stud- Only one species, Pieris occidentalis, a fa- ies of Rhopalocera in a high Sierran community— mous hilltopper, covers most of that period. Donner Pass, California. I. Butterfly associations and distributional factors. Lepid. Soc. One alpine species found elsewhere in the J. 16: 23-44. Donner Pass vicinity {Parnassiiis phoebus S., 1963. but- Garth, J. and J. W. Tilden. Yosemite behrii Edw.) has not been found on Basin- terflies. Res. Lepid. 2: 1-96. J. Castle Peak, apparently because its host, Se- Johnson, K., and G. Balogh. 1977. Studies in the Lycaeninae (Lycaenidae). 2. and evolu- dum obtusatiim Gray, is extremely rare on tion of the Nearctic Lycaena rubidus complex, the andesite substrate. It is common on with description of a new species. Bull. AUyn granite, and the butterfly is thus effectively Mus. 43: 1-62. edaphically restricted. It ranges north to Munz, p. a. 1970. A California flora. Univ. Calif. Press, Berkeley, Los Angeles and London. 1681 Plumas County, where it occurs at consid- erably lower elevations. pp. Shapiro, A. M. 1975. Genetics, environment, and sub- The isolated character of alpine "islands" species differences: the case of Polites sabuleti in the northern and north-central Sierra (: Hesperiidae). Great Basin Nat. makes them ideal subjects for biogeographic 35: 33-38. Smiley, F. 1921. A report upon the boreal flora of analysis. As Lepidopterists become less au- J. the Sierra Nevada of California. Univ. Calif. Publ. tomobile-bound, increasing amounts of data Bot. 9: 1-423. may become available which will help in Smith, G. L. 1973. A flora of the Tahoe Basin and 31: 1-231. the eventual formulation of a biogeographic neighboring areas. Wasmann J. Biol. Tilden, W. 1958. The butterfly associations of Tioga synthesis of the sources of our high-eleva- J. Pass. Wasmann Biol. 17: 249-271. tion fauna. In the meantime, the elevational J. True, G. H. 1973. The ferns and seed plants of Ne- and associational flexibility of so many Sier- vada County, California. Privately circulated ms, ran butterflies underscores the applicability 63 pp. of the "individualistic" approach to their