This paper provides the synonymy for the 13 species of Eschscholzia that I recognize. The only hope of understanding the genus lies in the living plants, and old collections and old descriptions should be used only as long as they are helpful and be ignored the moment they become confusing. Nevertheless, a reasonably coherent synonymy may eliminate needless toil for future students of the genus. By perusal of the descriptions and in some cases examination of the types I have been able to assign most of the epithets.

1. Eschscholzia californica Chamisso in Nees von Esenbeck, Horae Physicae Berolinenses 73. 1820.
   E. californica ssp. californica.
   • E. absinthifolia Greene, Pittonia 5:239. 1905.
   • E. ambigua Greene, Flora Franciscana 286. 1892.
   • E. angularis Greene, Pittonia 5:238. 1905.
   • E. apiculata Greene, Pittonia 5:235. 1905.
   • E. austinae Greene, Bull. California Acad. Sci. 1:69. 1885.
   • E. arvensis Greene, Pittonia 5:253. 1905.
     • E. arvensis var. dilatata Greene, Pittonia 5:253. 1905.
     • E. arvensis var. orthodichasialis Fedde, Rep. Nov. Spec. 3:105. 1906
   • E. australis Greene, Pittonia 5:249. 1905
   • E. benedicta Greene, Pittonia 5:228. 1905.
   • E. bernardina Greene, Pittonia 5:255. 1905
     • E. bernardina var. coarctata Fedde, Rep. Nov. Spec. 3:183.1906.
   • E. bicornuta Greene, Pittonia 5:249.1905.
   • E. biolettii Greene, Pittonia 5:249. 1905.
   • E. brandegii Greene, Pittonia 5:248. 1905.
   • E. californica vars.:
     • ambigua (Greene) Jepson, Flora W. Middle California 208. 1901.
     • compacta (Walpers) Jepson, Flora W. Middle California 208. 1901.
     • crocea (Bentham) Jepson, flora W. Middle California 207. 1901.
     • douglasii (Hooker & Arnott) Jepson, Flora W. Middle California 208. 1901.
     • luxurians Fedde, Rep. Nov. Spec. 3:27. 1906.
     • maritima (Greene) Jepson, Flora of California 1:570. 1922.
     • peninsularis (Greene) Munz, Man. South. California Fl. 181. 1935.
     • stricta (Greene) Jepson, Flora of California 1:570. 1922.
   • E. calosperma Greene, Pittonia 5:246. 1905.
   • E. caruifolia Greene, Pittonia 5:281. 1905.
     • E. caruifolia var. cyathifera (Greene) Fedde, Rep. Nov. Spec. 2:147. 1906.
   • E. chartacea Fedde. Rep. Nov Spec. 3:105. 1906.
   • E. clevelandii Greene, Pittonia 5:248. 1905.
   • ?E. cognata Greene, Pittonia 5:252. 1905.
   • E. columbiana Greene, Pittonia 5:231. 1905.
   • (Chryseis compacta Lindley, Bot. Reg. t. 1948. 1837)
     • E. compacta (Lindley) Walpers, Rep. 1:116. 1843.
   • E. confinis Greene, Pittonia 5:237. 1905.
   • E. crocea Bentham, Trans. Hort. Soc. Ser. 11 1:407.1835.
     • E. crocea var. apiifolia Greene, Pittonia 5:241. 1905.
     • E. crocea var. longissima Greene, Pittonia 5:241. 1905.
     • E. crocea var. sanctarum Greene, Fedde, Rep. Noc. Spec. 2:147. 1906.
   • E. cucullata (Greene), Erythea 2:120. 1894.
   • E. cyathifera Greene, Pittonia 5:263. 1905.
   • E. debilis Greene, Pittonia 5:227. 1905.
   • ?E. diversiloba Greene, Pittonia 5:256. 1905.
   • (Chryseis douglasii Hooker & Arnott) Walpers, Rep. 1:116.1843.
     • E. douglasii (Hooker & Arnott) Walpers, Rep. 1:116. 1843
   • E. eastwoodae Greene, Pittonia 5:227. 1905.
   • E. floribunda Greene, Pittonia 5:247. 1905.
     • E. floribunda var. gorgonica Greene, Pittonia 5:247. 1905.
   • E. foeniculacea Greene, Pittonia 5:224. 1905.
   • E. gigas Fedde, Rep. Nov. Spec. 3:28. 1906.
   • E. glauca Greene, Pittonia 1:45. 1887
   • E. granulata Greene, Pittonia 5:235. 1905.
     • E. granulata var. minuscula Fedde, Rep. Nov. Spe. 2:147. 1906.
   • E. helleriana Greene, Pittonia 5:229. 1905.
     • E. helleriana var. tilingii Fedde, Rep. Nov. Spec. 3:27. 1906.
   • E. humilis Greene, Pittonia 5:265. 1905.
   • E. inflata Greene, Pittonia 5:264. 1905.
   • E. isostigma Greene, Pittonia 5:254. 1905.
   • E. juncea Greene, Pittonia 5:228. 1905.
   • E. lacera Greene, Pittonia 5:250. 1905.
   • E. leptandra Greene, Pittonia 1:170. 1888.
   • E. leptomitra Greene, Pittonia 5:265.1905.
   • E. leucosticta Greene, Pittonia 5:229. 1905.
   • E. macrantha Greene, Pittonia 5:242. 1905.
   • E. marcida Greene, Pittonia 5:233. 1905.
     • E. marcida var. monticola Greene, Pittonia 6:233. 1905.
   • E. maritima Greene, Pittonia 1:60. 1887.
   • E. menziesiana Greene, Pittonia 5:223. 1905.
     • E. menziesiana var. anemophila Greene, Pittonia 5:223. 1905.
     • E. menziesiana var. coarctata Fedde, Rep. Nov. Spec. 2:148.1906.
     • E. menziesiana var. nesiaca Fedde, Rep. Nov. Spec. 2:148. 1906.
     • E. menziesiana var. recedens Greene, Pittonia 5:223. 1905.
   • E. microdonta Greene, Pflanzenreich 4, Fam. 104:167. 1909.
   • ?E. microloba Greene, Pittonia 5:250. 1905.
   • E. nevadensis Fedde, Rep. Nov. Spec. 2:146. 1906.
   • E. nitrophila Fedde. Rep. Nov. Spec. 2:146. 1905
   • E. orcuttiana Greene, Pittonia 5:254. 1905.
   • E. peninsularis Greene, Bull. California Acad. Sci. 1:68. 1885.
   • ?E. petrophila Greene, Pittonia 5:259. 1905.
   • E. physodes Greene, Pittonia 5:259. 1905.
   • E. picta Greene, Pittonia 5:283. 1905.
   • E. procera Greene, Pittonia 5:255. 1905.
   • ?E. pseudalcicornis Fedde, Rep. Nov. Spec. 3:184.1906.
   • E. pseudoinflata Fedde, Rep. Nov. Spec. 3:75. 1906.
   • E. recta Greene, Pittonia 5:245. 1905.
   • E. revoluta Greene, Pittonia 5:247. 1905.
     • E. revoluta var. caudatocalyx Fedde, Rep. Nov. Spec. 3:105. 1906.
   • E. rigida Greene, Pittonia 5:244. 1905.
   • E. robusta Greene, Pittonia 5:266.1905.
   • E. sanctarum Greene, Pittonia 5:243. 1905.
   • E. scariosa Greene, Pittonia 5:243. 1905.
     • E. scariosa var. dichasiophora Fedde, Rep. Nov. Spec. 3:75. 1906.
   • E. setchelli Fedde, Rep. Nov. Spec. 3:183. 1906.
   • E. shastensis Greene, Pittonia 5:234. 1905.
   • E. straminea Greene, Pittonia 5:257. 1905.
   • E. stricta Greene, Pittonia 5.236. 1905.
   • E. tenuisecta Greene, Pittonia 1:169. 1888.
   • E. thermophila Greene, Pittonia 5:256. 1905.
   • E. tristis Fedde, Pflanzenreich 4, Fam. 104:170. 1909.
   • E. vernalis Greene, Pittonia 5:258. 1905.
   • E. wrigleyana Millspaugh & Nuttall, Field Mus. Pub. Bot. 5:109. 1923.
   • E. xylorrhiza Greene, Pittonia 5:238. 1905.
   • E. yainacensis Greene, Pittonia 5:234. 1905.
     • E. yainacensis var. modocensis Fedde, Rep. Nov. Spec. 3:28. 1906.
   E. californica ssp. mexicana (Greene) C. Clark, Syst. Bot. 3:xxx. 1978.
   • E. aliena Greene, Pittonia 5:260. 1905.
   • E. arizonica Greene, Pittonia 5:261. 1905
   • E. douglasii (Hooker & Arnott) Walpers var. parvula A. Gray, Smiths. Contr. Knowledge 5:10. 1853.
   • E. jonesii Greene, Pittonia 5:261. 1905.
   • E. mexicana Greene, Bull. California Acad. Sci. 1:69. 1885.
   • E. parvula (A. Gray) Cockerell, Bot. Gaz. 26:279. 1898.
   • E. scapifera Fedde, Notizblatt 4:153.1904

2. Eschscholzia caespitosa Bentham, Trans. Hort. Soc. Ser. 11 1:408. 1835.
   • E. bakeri Greene, Pittonia 5:284. 1905.
   • ?E. biternata Greene, Pittonia 5:271. 1905.
   • E. californica Chamisso var. tenuifolia (Bentham) Curran, Proc. California Acad. Sci Ser. 2, 1:246. 1888.
   • ?E. cruciata Greene, Pittonia 5:279. 1905.
   • ?E. dolichocarpa Eastwood, Bull. Torrey Bot. Club. 30:487. 1903.
   • E. douglasii (Hooker & Arnott) Walpers var. tenuifolia (Bentham) Torrey, Pacific RR. Repts. 4:64. 1857.
   • E. dumetorum Greene, Pittonia 5:283. 1905.
   • E. elmeri Greene, Pittonia 5:286. 1905.
   • ?E. flaccida Fedde, Notizblatt 4:153. 1904.
   • ?E. formosa Greene, Pittonia 5:288. 1905.
     • ?E. formosa var. urocalyx Fedde, Rep. Nov. Spec. 3:184. 1906.
   • E. incisa Greene, Pittonia 5:287. 1905.
   • ?E. oregana Greene, Pittonia 5:282. 1905.
   • ?E. pusilla Greene, Pittonia 5:281. 1905.
   • E. rostellata Greene, Pittonia 5:282. 1905.
   • E. tenuifolia Bentham, Trans. Hort. Soc. Ser. 11 1:408. 1835.
   • E. tenuissima Greene, Pittonia 5:285. 1905

3. Eschscholzia parishii Greene, Bull. California Acad. Sci. 1:183. 1885.
   • E. minutiflora S. Watson var. parishii (Greene) Jepson. Flora of California 1:573. 1922.
   • E. ptarmicoides Greene, Pittonia 5:270.1905.
   • E. quadrangularis Greene, Pittonia 5:264.1905.

4. Eschscholzia covillei Greene, Pittonia 5:275. 1905
   • E. minutiflora S. Watson var. darwinensis Jones, Contr. W. Bot. 8:2. 1898.

5. Eschscholzia minutiflora S. Watson, Proc. Amer. Acad. Arts Sci. 11:122. 1876.
   • E. ludens Greene, Pittonia 5:272. 1905.
   • E. micrantha Greene, Pittonia 5:277. 1905.
     • E. micrantha var. fusigemmata Fedde, Rep. Nov. Spec. 3:184. 1906.
   • E. minuscula Greene, Pittonia 5:270. 1905.
   • E. minutiflora var. rutaefolia (Greene) Jepson, Flora of California 1:573. 1922.
   • E. modesta Greene, Pittonia 1:169. 1888.
   • E. multicaulis Fedde. Rep. Nov. Spec. 2:145. 1906.
   • E. rutaefolia Greene, Pittonia 5:271. 1905.
   • E. tortuosa Greene, Pittonia 5:278. 1905.

6. Eschscholzia glyptosperma Greene, Bull. California Acad. Sci. 1:70. 1885.

7. Eschscholzia lemmonii Greene, West Amer. Sci. 3:157. 1887.
   • E. lemmonii var. cuspidata Greene, Pittonia 5:289. 1905.
   • E. lemmonii var. laxa Greene, Pittonia 5:289. 1905.
   • E. caespitosa Bentham ssp. kernensis Munz, Aliso 4:90. 1958.
   • E. urceolata Eastwood, Bull. Torrey Bot. Club 30:488.1903.

8. Eschscholzia hypecoides Bentham, Trans. Hort. Soc. Ser. 11, 1:408. 1835.
   • E. alcicornis Greene, Pittonia 5:273. 1905.
   • E. asprella Greene, Pittonia 5:272. 1905.
   • E. caespitosa Bentham var. hypecoides (Bentham) A. Gray, Proc. Amer. Acad. Arts Sci. 22:272. 1887. (As to type.)
   • E. delitescens Fedde, Rep. Nov. Spec. 3:185. 1906.
   • E. eximia Greene, Pittonia 5:273. 1905.
   • E. lemmonii Green var. asprella (Greene) Jepson, Flora of California 1:573. 1922.

9. Eschscholzia rhombipetala Greene, Bull. California Acad. Sci. 1:71. 1885.
   • E. caespitosa Bentham var. rhombipetala (Greene) Jepson. Flora of California 1:574. 1922.

10. Eschscholzia lobbii Greene, Pittonia 5:290. 1905.
    • E. graminea Fedde, Rep. Nov. Spec. 2:146. 1906.
    • E. pulchella Greene, Pittonia 5:291. 1905.
    • E. unguiculata Greene, Pittonia 5:292. 1905.

11. Eschscholzia ramosa (Greene) Greene, Bull. Torrey Bot. Club 13:217. 1886.
    • E. ramosa var. trichophylla (Greene) Fedde, Rep. Nov. Spec. 2:147. 1906.
    • E. crossophylla Greene, Pittonia 5:268. 1905
    • E. elegans Greene var. ramosa Greene, Bull. California Acad. Sci. 1:182.1885.
    • E. trichophylla Greene, Pittonia 5:268.1905.

12. Eschscholzia elegans Greene, Bull. California Acad. Sci. 1:182. 1885.
    • ?E. crassula Greene, Pittonia 5:266. 1905.

13. Eschscholzia palmeri Rose, Contr. Nat. Herb. 1:23.1890.
    • Petromecon palmeri (Rose) Greene, Pittonia 5:293. 1905.
    • Petromecon frutescens Greene, Pittonia 5:294. 1905.
    • Eschscholzia frutescens (Greene) J.T. Howell, Leafl. W. Bot. 3:149. 1942.

SPECIES INCERTAE SEDIS

• E. exilis Greene, Pittonia 5:265. 1905.
• E. pseudopracox Fedde, Notizblatt 4:153. 1904.

Both these species, from the single collection Palmer 794, by their desciptions resemble somewhat E. californica, but the location is nearly 250 km south of the southernmost known populations of E. californica in Baja California. The location is even slightly south and west of the known distribution of E. minutiflora, and the descriptions do not match that species at all. I visited the region in the spring of 1978, which was a year of exceptional wildflower displays, and saw no Eschscholzias. If the plants are indeed E. californica, they may be relicts of a more southern full-glacial distribution.

• E. paupercula Greene, Pittonia 5:262. 1905.

In description this species somewhat resembles E. mexicana. Nevertheless, Munz (1959) included it in E. glyptosperma, although the seeds are not described as resembling the latter species at all. Plants of E. parishii have been found with the same cartilaginous ring around the hypanthium as E. paupercula, so until I can see the type I am unwilling to assign this species.

• E. vaccarum Greene, Pittonia 5:282. 1905.

This species, which could answer to E. caespitosa or even E. californica, was collected near Malheur Lake in Oregon, nearly 200 km from the nearest populations of either of these species and well out of range for Eschscholzia as a genus.