Psychotria kaduana (Cham. & Schltdl.) Fosberg, Occas. Pap. Bernice Pauahi Bishop Mus. 23(2): 43, 1962.

Berger, Andreas, 2018, Rediscovery of Chamisso's type specimens of Hawaiian Psychotria (Rubiaceae, Psychotrieae) in the herbarium of the Natural History Museum, Vienna, PhytoKeys 114, pp. 27-42 : 27

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Psychotria kaduana (Cham. & Schltdl.) Fosberg, Occas. Pap. Bernice Pauahi Bishop Mus. 23(2): 43, 1962.


Psychotria kaduana (Cham. & Schltdl.) Fosberg, Occas. Pap. Bernice Pauahi Bishop Mus. 23(2): 43, 1962.

Coffea kaduana Cham. & Schltdl., Linnaea 4(1): 33-35, 1829a. ≡ Straussia kaduana (Cham. & Schltdl.) A.Gray, Proc. Amer. Acad. Arts 4: 43, 1860. Type. USA. Hawaii: Oahu, Southern Waianae Range, <730 m alt., 7-10 Oct 1817, or, Southern Koolau Range, <730 m alt., 12 Oct 1817, L.K.A. von Chamisso s.n. (lectotype, designated here: W-Endl. 0065914!); Oahu, Kahuauli Ridge, 500-750 m alt., 17 Dec 1931, E. Christophersen & E. Hume 1426 (epitype, designated here: BISH barcode 1010994!, Sohmer 1977: fig. 52!).

General remarks.

Psychotria kaduana ( sect. Straussia (DC.) Fosberg) is the most widely distributed species of Hawaiian Psychotria . It is found on the islands of Kauai, Oahu, Molokai, Lanai and Maui. It possesses a wide ecological amplitude resulting in considerable morphological variation and many local forms, some of which have received taxonomic recognition. However, it was shown that these all intergrade and are best treated as a single polymorphic species. A detailed synonymy and description of P. kaduana including lists of specimens, distribution maps, drawings and photos illustrating morphological variations are found in Sohmer (1977: 148-159) and Wagner et al. (1999). According to molecular phylogenetic data, this species belongs to the " greenwelliae " clade, which also comprises P. fauriei (H. Lév.) Fosberg, P. greenwelliae Fosberg, P. hathewayi Fosberg, P. hawaiiensis var. hillebrandii (Rock) Fosberg and P. mauiensis Fosberg ( Nepokroeff et al. 2003).


The protologue of Psychotria kaduana lacks information about the etymology of the name, but a person called “Kadu” is frequently mentioned in Chamisso’s publications. While visiting the Aur Atoll (Ratak Chain, Marshall Islands) in February 1817, the Rurik was approached by Kadu, a native of Woleai ( “Ulea”), an atoll in the eastern Caroline Islands, Federated States of Micronesia. Four years before, a storm bore Kadu’s boat far to the east and, after months at sea, he finally reached the Ratak Chain. With curiosity and the intention of being dropped off closer to home, he joined the expedition and became a close friend of Chamisso and his prime source of ethnographic information on Micronesia. After visiting distant places such as Alaska and Hawaii, the expedition returned to the Ratak Chain in November 1817, where Kadu finally settled in the Wotje Atoll ( Chamisso 1818: 203, 1836a: 278-280; Kotzebue 1821: 86-93; Maaß 2016; Igler 2017).

Chamisso wrote with great admiration about his "companion, teacher and dearest friend" Kadu, and dedicated to him the genus Kadua Cham. & Schltdl., a group of Pacific Rubiaceae -Spermacoceae with its centre of diversity on the Hawaiian Islands ( Chamisso and Schlechtendal 1829b: 157-158 "Nomen in honorem amicissimi Kadu ex Ulea, dulcissimi nobis in expecitione Romanzoffiana per aliquot menses sodalist atque magistri", Terrell et al. 2005). A naturalistic lithographed portrait of Kadu in his traditional dress is given by the expedition’s artist Choris (1822: Iles Sandwich, pl. 17). The same portrait with European dress is found in the honorary frontispiece of Chamisso’s expedition report (1836b), once more illustrating Chamisso’s connection with Kadu. Ultimately, it may not be clarified if the epitheton " kaduana " refers to a superficial resemblance with the genus Kadua , the person Kadu or both.


The protologue of Psychotria kaduana gives the type information as "In nemorosis montium Insulae O-Wahu A. D. 1817 legimus" ( Chamisso and Schlechtendal 1829a: 33-35). Information provided in the itinerary ( Chamisso 1826: 7-8) allows dating of their second visit to Oahu and the period in which the type collection was made to the time between 2 and 14 October 1817. The diary of Chamisso (1836a: 344) provides additional information about their collecting activities and reports only two occasions where plants have been collected during that visit.

Between 7 and 10 October 1817, Chamisso explored the "western mountain range of the island" ( Chamisso 1836a: 344), which he and his two guides climbed from around Pearl River. Likely, the information denotes the Waianae Range, the western of the two mountain ranges on the island of Oahu. During that time, Eschscholtz suffered from a sore leg, could not attend the expedition and was left in care of drying previous collections on board the Rurik. On the 12th of October 1817, Eschscholtz had recovered and both made a daytrip to "the mountains", this time denoting the Koolau Range behind Honolulu ( Chamisso 1836a: 342, 344-347).

At the Herbarium of the National History Museum (W), a peculiar specimen of P. kaduana is preserved (Figure 1 View Figure 1 ). The sheet contains a small sterile branchlet and a capsule with some leaves, an inflorescence and an immature fruit. The label gives the names " Coffea kaduana " and " Coffea kaduana Cham." in two different hands as well as the island "O. Wahu", but no information about the collector. On the upper right corner, "Hb. Endl." in ink indicates that the specimen originated from the private herbarium of Stephan Ladislaus Endlicher (1804-1849) and which he presented to the Botanical Museum after he was appointed curator ( Torrey 1836; Anonymous 1845). Sohmer (1977: 157) subsequently confirmed the identification of the specimen and cited it as "Oahu without specific locality, Endlicher s.n. (W)".

Endlicher, however, never visited the Hawaiian Islands, so the respective specimen was not collected by him. The age of the specimen, the name and the locality on the label indicate that it could be original material of Psychotria kaduana . Comparison with specimens at LE (e.g. Imchanitzkaja 2004; Popov 2014; Maaß 2016: 149-170) and HAL (international herbarium database JACQ, shows that Chamisso’s labels are characteristic in size, paper and handwriting and confirm that this specimen was indeed collected by Chamisso. Therefore, it constitutes type material for P. kaduana .

Concerning the history of the specimen, Endlicher was professor of botany, director of the Botanical Garden and the Botanical Museum of Vienna from 1839-1849 ( Anonymous 1849). As one of the foremost systematicists, taxonomists and prolific writers of his time (e.g. Flora brasiliensis, Nova genera et species plantarum, Genera plantarum), he was in contact with many contemporary botanists. A letter preserved in the Berlin State Library ( Endlicher 1833), shows that he was in correspondence with Chamisso and that they exchanged specimens. This could explain how Chamisso’s specimens from the Romanzoffian Expedition came into the possession of Endlicher.

The rediscovery of a type specimen of P. kaduana at W supersedes the neotypification of Sohmer (1977; ICN, Art. 9.19). Although rather fragmentary, the respective specimen is the only original material known and is here designated as the lectotype of this name (ICN, Art. 9.11). In order to maintain nomenclatural stability, the former neotype E. Christophersen & E. Hume 1426 (BISH) is additionally designated as an epitype to support the limited lectotype material (ICN, Art. 9.8).














Psychotria kaduana (Cham. & Schltdl.) Fosberg, Occas. Pap. Bernice Pauahi Bishop Mus. 23(2): 43, 1962.

Berger, Andreas 2018

Straussia kaduana

A. Gray 1860

Coffea kaduana

Cham & Schltdl 1829