The Nomenclatural and Taxonomic Status of the Hawaiian Shrub Scaevola gaudichaudii H. & A.I GEORGE W. GILLETT2

IN HIS TREATMENT of the genus Scaevola in more closely adapted to dry-land habitats than Hawaii, Skottsberg (1927) assigned the name is any other species, and it is the only one in Scaevola menziesiana Chamisso to a species that which the inflorescence consists of a single occurs on the six major Hawaiian islands, but flower (Fig. 1). These features clearly delineate which he apparently had not seen in nature. He this species, and its ecological and morphological cited many specimens from earlier collectors attributes merit a more clearly expressed account but none of his own. In reference to flower color than has been available heretofore. he commented: "The corolla is said to be yel­ In my work on the genus Scaevola in the low. Fresh material of this interesting form is Hawaiian Islands, all species have been studied very desirable." in the field. These include the rare, nearly ex­ Let it suffice here to say that the first name tinct S. coriacea Nutt., and the rare but locally applied to this species was Scaevola montana abundant S. kilaueae Degener. While Degener Gaudichaud, a name that had already been ap­ (1933) stated that the flowers of S. kilaueae are plied to a Scaevola from New Caledonia by yellow, this applies only to pressed specimens. Labillardiere. Noting this earlier application of The extensive population of this species just Gaudichaud's name, Hooker and Arnott as­ south of Kilauea Volcano on the island of signed the name Scaevola gaudichaudii to Lay Hawaii is characterized by white flowers that and Collie's collection of this taxon, and this is turn yellow upon desiccation. It is true that the the correct name for the species we are dealing yellow-flowered S. gaudichaudii has been col­ with. lected only a few miles west of the above lo­ In my recent cytological study of Scaevola in cality, and it is possible that there is some inter­ Hawaii, I have found that all species are char­ gradation between these two species. However, acterized by the chromosome number .n = 8. no such intergradation is known or claimed here, The related genus Camphusia, remarkable for although it is conceded that the two species its non-bracteate flowers suggestive of Clermon­ have similarities. However, there is an even tia, is unique in being tetraploid (n = 16), in closer similarity between S. gaudichaudii and having most distinctive pollen (Selling, 1947), S. gaudichaudiana on the islands of Oahu and and in other features that need not be elaborated Kauai, where there is strong indication of inter­ here. The genus Scaevola, in the framework of gradation between the two species. It is unfor­ this paper, is considered distinct from the lat­ tunate that two similar species should carry ter. such correspondingly similar names as to cause In the present view of the genus Scaevola in confusion in field and laboratory references, but Hawaii, S. gaudichaudii is a most interesting such are the problems encountered in applica­ species on several counts. It is the only species in tion of the International Code of Botanical which the corollas are distinctly yellow. Among Nomenclature. the other species, S. mollis is characterized by My first impression upon encountering an ex­ violet flowers, and' the flowers of all others are tensive population of Scaevola gaudichaudii white, or white with some degree of violet pig­ above Lahainaluna, West Maui, was that here mentation. In addition, S. gaudichaudii is much was a very distinct species. A perusal of Hille­ brand (1888) shows that this species, quite I This study was supported by the Committee on possibly the same population, had been examined Research, Academic Senate, University of California, and collected by early botanists. This popula­ Riverside. Manuscript received March 25, 1968. tion includes well over 100 plants at various 2 Department of Life Sciences, University of Cali­ fornia, Riverside, California 92502. stages of maturity, including many of consider- 125 126 PACIFIC SCIENCE, Vol. XXIII, January 1969

B • .,~ 1'1 I •

o 1 '----' em mm

~.

\ ; F

o 2- L.--.-J mm

FIG. 1. Scaevola gaudichaudii H. & A., drawn from Gillett 2006. A, Flowering branch; B, chromosome complement (n = 8) at first metaphase of meiosis; C, flower just prior to anthesis; D, axillary inflorescences and flower at anthesis; E, mature fruit; and P, flower after separation of the corolla, showing receptive tis­ sue of the stigma. able size. The uniformity of the population is and 500 meters, on a unique geological forma­ expressed in flower color (apricot yellow: tion that is marked by a gray coloration of the Ridgway, 1912), inflorescence, leaf form, habit, parent rock. The area has a relatively low rain­ and fruits. There can be no doubt that this is fall and the habitat is distinctly dry-land forest a distinct species and that it is not a minor var­ in character, the associated genera including the iant of the related S. gandichattdiana. This pop­ rare indigenous genus Gouania. Among the up­ ulation is growing at elevations between 250 land Hawaiian Scaevolae, this species has the Scaevola gaudichaudii-GILLETT 127

strongest adaptation to endangered and deci­ sinking in fresh water and sea water. Chromo­ mated dry-land habitats. It has been collected some number is n = 8. on such habitats on all of the six major islands. TYPE: Collected in the Hawaiian Islands by However, the only recent collections are from Lay and Collie of Captain Beechey's Voyage. Lahainaluna, and it is certain that the other Type not seen. populations have been severely decimated. DISTRIBUTION: Upland dry ridges between 250 and 800 meters with annual rainfall of ap­ Scaevola gaudichaudii H. & A. Bot. Capt. proximately 40 em. On relatively open habitats, Beechey's Voy., p. 89, 1832. with Dodonaea, Osmanthtts, Gouania, Styphelia, Scaevola montana Gaudichaud. Voyage autour Bidem, Canthium, Wikstroemia, and other dry­ du monde, fait par Ordre du Roi l' Uranie land indigenous and exotic species. This species et la Physicienne, pp. 460-461, 1829. Not occurs on the islands of Kauai, Oahu, Molokai, Scaevola montana Labillardiere, 1825. Lanai, Maui, and Hawaii. Scaevola menziesiana Chamisso. Linnaea SPECIMENS EXAMINED:3 KAUAI: Milolii 8:277, 1833. Ridge, Waimea, St. John and Fosberg 13726, Scaevola swezeyana Rock. Bull. Torrey Bot. 13730, 13737; Makaha Ridge, 1500 feet, Judd Club 36, 1909. 79; flats back of Mana, Rock 16039. OAHU: Temminckia gaudichaudii De Vriese. Ned. Kulepiamoa Ridge, Niu, 1,000 feet, St. John Kruidk. Archief 2:144, 1854. 20,109; Kawailoa Ridge, Degener 19,510; Wai­ lupe, -l- 400 m Russ s. It.; Kaimuki Ridge, Forbes Glabrous ovoid to globose shrub 0.5-2 m 1857-0; middle ridge, Niu Valley, Degener high, the form expressed by divaricate, ascend­ 7763; Palolo Valley, Rock 14135; Palama Trail, ing branches; leaves with petioles 0.5-1.5 em -l- 300 m, Jttdd 62; Kaaawa Valley, 325 m, long, the glabrous blades coriaceous, lanceolate Judd 60; Kuaokala Forest Res., Waianae Mts., to oblanceolate, up to 4.5 em long and 1.2 em -l- 1500 feet, Hosaka 1293. MOLOKAI: Pukoo broad, equilateral and cuneate-attenuate at base, ridges, Forbes 349-MO; Kahuaawi Gulch, De­ rounded to obtuse to acute at apex, entire to gener 17247. LANAI: Mahana, Rock 8129; serrate at margins with 1 or 2 teeth per em, the Kanepuu Point, Munro s. n.; Kaiholena, Mttn1'O primary veins 1-3 per side, curved upward at 47. WEST MAUl: Lahainaluna, Forbes 310-M; margins; inflorescence borne in the leaf axil, ridge above Lahainaluna, 400-800 m, Gillett consisting of a single flower on a pedicel 0.5 2006. EAST MAUl: Kealii, south slope of Halea­ em long, the pedicel terminated by a pair of kala, Forbes 212-M. HAWAII: Kahuku, Kau equal, linear bracts 3-4 mm long; ovary ca. 3 District, on aa lava land, -l- 1500 feet, L. W. mm long, surmounted by 5 rounded, glabrous Bryan s. n. calyx lobes scarcely 0.5 mm high; corolla 2-2.5 em long, the linear lobes glabrous on outer sur­ face, pubescent on inner surface with hairs ca. LITERATURE CITED 0.5 mm long, the lobes apricot yellow with DEGENER, O. 1933. Flora Hawaiiensis. Hono­ brown mid-vein and marginal veins; stamens lulu, published by the author. 7 mm long, the anthers basifixed, 2 mm long, HILLEBRAND, W. 1888. Flora of the Hawaiian the glabrous filaments 5 mm long, erect at an­ Islands. Heidelberg, C. Winter. thesis; style 2-2.5 em long, equal to the corolla, RIDGWAY, R. 1912. Color standards and color densely pubsecent with hairs 0.5 mm long, the nomenclature. Washington, D. c., published stigma at early anthesis covered with a ciliate by the author. indusium that retains pollen, the stigma growing SELLING, O. H. 1947. Studies in Hawaiian pol- after anthesis, producing receptive tissue that presumably would permit outcrossing; the corolla, stamens, and style separating from the 3 All specimens are in the herbarium of the B. P. summit of the ovary after anthesis; fruit a Bishop Museum, Honolulu. The kindness of Dr. Pieter van Royen, Head of the Department of Botany, glabrous, dark purple, ovoid drupe, when dry in making these specimens available for study is 5 mm long and 4 mm broad, the 2-celled stone gratefully acknowledged. 128 PACIFIC SCIENCE, Vol. XXIII, January 1969

len statistICs, Part II. Bernice P. Bishop SKOTTSBERG, C. 1927. Artemisia, Scaevola, Museum Special Publication 38, pp. 322-323, Santalum, and Vaccinium of Hawaii. Bernice pI. 50, figs. 788-799. P. Bishop Museum Bulletin 43, pp. 16-39.