| Name | Author | Source | Citation | Year |
|---|---|---|---|---|
| Alaria tenuifolia | Setchell in Setchell & Gardner | Univ. Calif. Publ. Bot. | 1: 273, pl. 22 | 1903 |
| Alaria valida | Kjellman & Setchell in Setchell & Gardner | Univ. Calif. Publ. Bot. | 1: 278, pl. 21: figs. 32, 33 | 1903 |
| Amphiroa aspergillum f. nana | Setchell & N.L. Gardner | Univ. Calif. Publ. Bot. | 1: 359 | 1903 |
| Amphiroa tuberculosa f. californica | (Decaisne) Setchell & N.L. Gardner | Univ. Calif. Publ. Bot. | 1: 361 | 1903 |
| Amphiroa tuberculosa f. frondescens | (Postels & Ruprecht) Setchell & N.L. Gardner | Univ. Calif. Publ. Bot. | 1: 362 | 1903 |
| Amphiroa tuberculosa f. orbigniana | (Decaisne) Setchell & N.L. Gardner | Univ. Calif. Publ. Bot. | 1: 362 | 1903 |
| Anatheca furcata | Setchell & N.L. Gardner | Univ. Calif. Publ. Bot. | 1: 310, pl. 23: fig. 39; pl. 24: fig. 41 | 1903 |
| Callophyllis furcata f. dissecta | Farlow ex Setchell & N.L. Gardner | Univ. Calif. Publ. Bot. | 1: 306 | 1903 |
| Cladophora columbiana | Collins in Setchell & N.L. Gardner | Univ. Calif. Publ. Bot. | 1: 226 | 1903 |
| Codium ritteri | Setchell & N.L. Gardner | Univ. Calif. Publ. Bot. | 1: 231, pl. 17: figs. 8-11 | 1903 |
| Collinsiella tuberculata | Setchell & N.L. Gardner | Univ. Calif. Publ. Bot. | 1: 204-205, pl. 17: figs. 1-7 | 1903 |
| Colpomenia sinuosa f. deformans | Setchell & N.L. Gardner | Univ. Calif. Publ. Bot. | 1: 242, pl. 18: figs. 13-15 | 1903 |
| Colpomenia sinuosa f. tuberculata | (Saunders) Setchell & N.L. Gardner | Univ. Calif. Publ. Bot. | 1: 242 | 1903 |
| Corallina officinalis f. multiramosa | Setchell & N.L. Gardner | Univ. Calif. Publ. Bot. | 1: 366 | 1903 |
| Corallina officinalis f. robusta | Setchell & N.L. Gardner | Univ. Calif. Publ. Bot. | 1: 365 | 1903 |
| Endocladia muricata f. compressa | Setchell & N.L. Gardner | Univ. Calif. Publ. Bot. | 1: 297 | 1903 |
| Fucus evanescens f. robustus | Setchell & N.L. Gardner | Univ. Calif. Publ. Bot. | 1: 283 | 1903 |
| Laminaria bullata f. subsimplex | Setchell & N.L. Gardner | Univ. Calif. Publ. Bot. | 1: 257 | 1903 |
| Laminaria saccharina f. complanata | Setchell & N.L. Gardner | Univ. Calif. Publ. Bot. | 1: 262 | 1903 |
| Lophosiphonia villum | (J. Agardh) Setchell & N.L. Gardner | Univ. Calif. Publ. Bot. | 1: 329 | 1903 |
| Platythamnion heteromorphum f. reversum | Setchell & N.L. Gardner | Univ. Calif. Publ. Bot. | 1: 345, pl. 25: fig. 42 | 1903 |
| Pleonosporium vancouverianum | (J. Agardh) Setchell & N.L. Gardner | Univ. Calif. Publ. Bot. | 1: 338 | 1903 |
| Pteridium serratum f. platyphyllum | Setchell & N.L. Gardner | Univ. Calif. Publ. Bot. | 1: 325 | 1903 |
| Rhodochorton subimmersum | Setchell & N.L. Gardner | Univ. Calif. Publ. Bot. | 1: 347, pl. 17: fig. 12 | 1903 |
| Rhodymenia palmata f. mollis | Setchell & N.L. Gardner | Univ. Calif. Publ. Bot. | 1: 315 | 1903 |