identifier	taxonID	type	CVterm	format	language	title	description	additionalInformationURL	UsageTerms	rights	Owner	contributor	creator	bibliographicCitation
6C345A09A9E153078B1B4D7AEC5D749B.text	6C345A09A9E153078B1B4D7AEC5D749B.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Peperomia kauaiana K. R. Wood & W. L. Wagner 2026	<div><p>Peperomia kauaiana K. R. Wood &amp; W. L. Wagner sp. nov.</p><p>Figs 1, 2, 3 A – C, 4</p><p>Diagnosis.</p><p>Peperomia kauaiana is morphologically most similar to P. degeneri Yunck. from which it differs by the following combination of characteristics: stem internodes 3–5 mm long (vs. 10–15 mm long), leaves 5 - to 7 - nerved, ovate to ovate-orbicular, 0.5–1.4 (– 1.8) cm long, margins revolute (vs. leaves 3 - nerved, elliptic to oblong-elliptic, 1.5–2 (– 3.5) cm long, margins flat), petioles 0.2–0.5 cm long (vs. petioles 0.8–1.2 cm long) and spikes 1.1–1.7 (– 2.2) cm long (vs. spikes 2.5–4.8 cm long).</p><p>Type.</p><p>USA. Hawaiian Islands, Kaua‘i: • Līhu‘e District, <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-159.501&amp;materialsCitation.latitude=22.014" title="Search Plazi for locations around (long -159.501/lat 22.014)">Wai‘ahi</a>, 22.014, - 159.501, 830 m alt., 4 Apr 2019 (fl. &amp; fr.), Wood, Perlman &amp; Query 18149 (holotype: PTBG 1000067990!; isotypes: BISH!, CAS!, MO!, NY!, US!) .</p><p>Description.</p><p>Herb, terrestrial, stems dark red to red-purple, decumbent or occasionally sub-erect, rooting at nodes, unbranched, rarely 2 - to 3 - branched in the upper part, 3–8 cm long, 1–2 mm in diameter towards the base; internodes 3–5 mm long, densely appressed hirtellous to strigulose, the hairs 0.3–0.5 mm long. Leaves alternate, thinly firm and fleshy, drying chartaceous, ovate, ovate-orbicular, rarely elliptic-ovate, 5–14 (– 18) mm × 4–11 (– 14) mm, palmately 5 - to 7 - nerved, upper surface dull, dark green, moderately appressed hirtellous, lower surface with veins usually dark red to purple, intercostal areas pale pink to red-purple or rarely green, moderately appressed hirtellous, margins revolute, apex acute, base subcordate to rounded or obtuse, rarely cuneate, petioles 2–5 mm long, densely appressed hirtellous. Spikes 1, rarely 2, terminal, 11–17 (– 22) mm long, peduncles red to purple, 4–7 × 0.3–0.4 mm, moderately appressed hirtellous, sometimes densely towards base, the fertile rachis glabrous, yellow-green, 7–14 × 1 mm, flowers moderately congested, bracts orbicular, ca. 0.5 mm diameter, stamens ellipsoidal, 2, ovary ovoid, apex oblique; stigmas terminal, shallowly cleft to bi-lobed. Fruits ovoid, 0.3–0.5 (– 0.8) mm long, dark brown, covered with sticky papillae.</p><p>Additional specimens examined</p><p>(paratypes). USA. Hawaiian Islands, Kaua‘i: Kōloa District, • Wahiawa, 670–975 m alt., 13 Apr 1991 (fr.), Flynn et al. 4595 (BISH, PTBG, US) • Kawaihau District, Makaleha Mountains, 823–920 m alt., 2 Jul 1993 (fl. &amp; fr.), Flynn et al. 5398 (PTBG) • Līhu‘e District, Wai‘ahi, 847 m alt., 22 Oct 2020 (fl. &amp; fr.), Wood et al. 18580 (BISH, CAS, PTBG, US) .</p><p>Phenology.</p><p>Peperomia kauaiana has been observed with flower and fruit during April, July and October.</p><p>Etymology.</p><p>The epithet refers to the island of Kaua‘i, oldest and most floristically rich of all the high Hawaiian Islands and the only known location for Peperomia kauaiana .</p><p>Vernacular name.</p><p>‘ Ala‘ala wai nui is the Hawaiian name for related species. Hawaiians used the ash of their burned leaves and stems as a grey-green dye in kapa making (Krauss 2001).</p><p>Affinities.</p><p>Lim et al. (2019) presented a phylogenetic analysis of plastomes that indicate four major lineages of Peperomia within the Hawaiian archipelago. Although many relationships within these clades are poorly resolved, additional preliminary analyses, based on recently developed target-enrichment nuclear data using the Angiosperms 353 probe set, corresponds closely with the findings of Lim et al. (2019). The four colonisation events of Peperomia to the Hawaiian Islands represent the largest number of colonisation events of any flowering plant genus to the archipelago (Howarth et al. 1997; Keeley and Funk 2011; Lim et al. 2019). Based on morphological similarity, Peperomia kauaiana belongs to the largest of these radiations, designated as ‘ Hawaiian radiation A’ by Lim et al. (2019).</p><p>Morphologically, Peperomia kauaiana is most similar to P. degeneri (Moloka‘i, Fig. 5), with both species having very small, strictly alternate leaves that are hirsute to densely hirtellous on both sides, yet P. kauaiana is generally a smaller plant and has revolute rather than flat leaf margins, along with other distinguishing characters noted in the diagnosis. Superficially, P. kauaiana can be confused with P. cookiana C. DC. (Kaua‘i, O‘ahu, Moloka‘i, Lāna‘i, Maui and Big Island of Hawai‘i), as both are relatively small herbs and have hirsute to hirtellous leaves and internodes. However, P. kauaiana has alternate leaves and P. cookiana has opposite or whorled leaves, 2–4 per node. Although P. alternifolia Yunck. (Moloka‘i, Lāna‘i and Maui, Fig. 6 B) and P. oahuensis C. DC. (Kaua‘i and O‘ahu, Fig. 6 C) are alternate-leaved like P. kauaiana, they differ in being entirely glabrous, whereas P. kauaiana has hirsute to hirtellous leaves, petioles, internodes and peduncles. The only other species that could potentially be confused with P. kauaiana is P. latifolia Miq. (Kaua‘i, O‘ahu, Moloka‘i, Lāna‘i, Maui and Big Island of Hawai‘i, Fig. 6 A), yet P. kauaiana differs from P. latifolia in having stem internodes 3–5 mm long, densely appressed hirtellous to strigulose (vs. internodes 10–30 (– 80) mm long, hirsute to subglabrate), leaves strictly alternate 5–14 (– 18) mm × 4–11 (– 14) mm, with revolute margins (vs. leaves alternate, opposite or whorled (20 –) 30–60 (– 75) mm × (15 –) 20–50 (– 65) mm, margins flat), adaxial leaf surface appressed hirtellous (vs. adaxial leaf surface glabrous or hirsute only towards base), petioles 2–5 mm long (vs. petioles 7–20 (– 30) mm long) and spikes 11–17 (– 22) mm long, fertile rachis 1 mm wide (vs. spikes (15 –) 20–80 (– 150) m long, fertile rachis 2–3 mm wide) (see Table 1 and key to Hawaiian Peperomia with alternate leaves). Note: We examined type collections of P. dentulibractea Miq. (Moloka‘i), P. punaluuna C. DC. (O‘ahu), P. villipeduncula C. DC. (O‘ahu) and P. waihoiana St. John (Maui), that were later synonymised with P. latifolia by Yuncker and others (de Condolle 1913; Yuncker 1933; Wagner et al. 1990, 1999) and agree that they fall within the circumscription of P. latifolia .</p><p>Distribution and ecology.</p><p>Peperomia kauaiana is endemic to the volcanic island of Kaua‘i where it is has been documented in lowland wet forest around the island’s eastern windward slopes between 670 and 975 m elevation. Location sites include the south-eastern ridges of Wahiawa, the central eastern ridges of Wai‘ahi and the north-eastern ridges of the Makaleha Mountains (Fig. 4). It has predominantly been observed growing terrestrially in layers of bryophytes and in the understorey of ferns. These wet forests are low-statured, range between 3000 and 6500 mm of precipitation per year and are rich in endemic plant species. Dominant genera include trees of Metrosideros Banks ex Gaertn. ( Myrtaceae) and Cheirodendron Nutt. ex Seem. ( Araliaceae) and large patches of matting ferns, such as Dicranopteris Bernh. and Diplopterygium (Diels) Nakai ( Gleicheniaceae). Other common tree and shrub genera include endemic species of Polyscias J. R. Forst. &amp; G. Forst. ( Araliaceae); Pritchardia Seem. &amp; H. Wendl. ( Arecaceae); Dubautia Gaudich. ( Asteraceae); Cyanea Gaudich. ( Campanulaceae); Antidesma L. ( Phyllanthaceae); Scaevola L. ( Goodeniaceae); Hydrangea Gronov. ( Hydrangeaceae); Geniostoma ( Loganiaceae); Coprosma J. R. Forst. &amp; G. Forst., Kadua Cham. &amp; Schltdl., Psychotria L. ( Rubiaceae); and Melicope J. R. Forst. &amp; G. Forst. ( Rutaceae). Genera of sedges include Carex L., Cyperus L. and Machaerina Vahl ( Cyperaceae). Smaller shrubs, herbs and vines include Astelia Banks &amp; Sol. ex R. Br. ( Asteliaceae); Bidens L. ( Asteraceae); Vaccinium L. ( Ericaceae); Cyrtandra J. R. Forst. &amp; G. Forst. ( Gesneriaceae); Freycinetia Gaudich. ( Pandanaceae); and Smilax L. ( Smilaceae). Occasional genera of ferns include Sadleria Kaulf. ( Blechnaceae); Cibotium Kaulf. ( Cibotiaceae); and Microlepia C. Presl ( Dennstaedtiaceae). Other Peperomia species in the nearby vicinity of P. kauaiana include three predominantly terrestrial species, P. cookiana, P. hesperomannii Wawra and P. latifolia (Fig. 6 A), along with one epiphytic species, P. oahuensis (Fig. 6 C).</p><p>Key to Hawaiian Peperomia with alternate leaves</p><p>Note: H = Hawai‘i (Big Island); K = Kaua‘i; L = Lāna‘i; M = Maui; Mo = Moloka‘i; O = O‘ahu.</p><p>Preliminary conservation assessment. IUCN Red List Category.</p><p>When evaluated using the World Conservation Union (IUCN) criteria for endangerment (IUCN 2012, 2024), Peperomia kauaiana falls into the Critically Endangered (CR) category, indicating a high risk of extinction in the wild. Our formal evaluation can be summarised by the IUCN hierarchical alphanumeric numbering system of criteria and subcriteria, CR B 1 ab (iii) + 2 ab (iii), which reflects a severely limited extent of occurrence (EOO) of 12 km 2, an area of occupancy (AOO) of less than 4 km 2, a wild population of only three small sub-populations consisting of 1500–2100 mature plants and a continuing decline in the quality of habitat inferred.</p><p>The continued decline in quality of habitat for P. kauaiana is evidenced by severe habitat degradation from invasive non-native mammals, such as pigs (Sus scrofa L.), rats ( Rattus spp.) and occasional goats ( Capra hircus), along with introduced slugs, insects and disease. Other serious threats include hurricane-force winds, flash floods, landslides triggered after torrential rains and invasive non-native plants that displace naturally occurring ones within P. kauaiana habitat, especially Sphaeropteris cooperi (Hook. ex F. Muell.) R. M. Tryon ( Cyatheaceae); Melastoma septemnervium Lour., Miconia crenata (Vahl.) Michelang. ( Melastomataceae); Psidium cattleyanum Sabine, Rhodomyrtus tomentosa (Aiton) Hassk. ( Myrtaceae); Axonopus fissifolius (Raddi) Kuhlm. ( Poaceae); Rubus rosifolius Sm. ( Rosaceae); and Buddleja asiatica Lour. ( Scrophulariaceae).</p><p>Notes on two possibly extinct Hawaiian Peperomia</p><p>Plant and animal endemics from isolated oceanic islands are more often critically endangered and highly susceptible to extinction, being particularly vulnerable and sensitive to invasive introductions of foreign plants and animals (Milberg and Tyrberg 1993; Kearns et al. 1998; Sakai et al. 2002; Wood 2012; Wood et al. 2019). The loss of suitable habitat on islands can be devastating to specialised species, especially considering their inherently limited land mass when compared to continental regions (Heinen et al. 2018). Currently, there are over 130 Hawaiian vascular plant taxa that are considered possibly extinct, including two Hawaiian Peperomia species, namely P. degeneri from Moloka‘i (Fig. 5) and P. subpetiolata Yunck. from Maui (Fig. 7) (Wood 2012; Wood et al. 2019). The following is a summary of where and when those two Peperomia species were observed and we encourage efforts be made to relocate them.</p><p>Peperomia degeneri (Fig. 5) has only been documented from two locations (Fig. 8). It was originally collected by O. Degener in 1928 on shaded cliffs along the east arm of Kalua‘aha Valley, Moloka‘i at an unrecorded elevation and was subsequently described by Yuncker in 1933. For many years, botanists studying the Hawaiian flora lost track of any wild populations and considered P. degeneri to be possibly extinct. Its re-discovery occurred in 2008, 80 years after Degener’s observation, when H. Oppenheimer made an herbarium collection around Waihānau Valley, Moloka‘i, at an elevation of 900 m. Unfortunately, when Oppenheimer returned to the site several years later, the colony of P. degeneri had perished, once again raising the possibility of its extinction.</p><p>It should be noted that, although Yuncker (1933) describes the spike of Peperomia degeneri as being up to 3 cm long, on careful examination of the isotype collections, we find that the spike (peduncle and fertile rachis) can be as long as 4.8 cm (see diagnosis and key to Hawaiian Peperomia with alternate leaves). It is also worth noting that P. degeneri has only been documented on vertical habitats, with Degener having found it on shaded cliffs and Oppenheimer on vertical stream banks.</p><p>Specimens of Peperomia degeneri examined. USA. Hawaiian Islands, Moloka‘i: • Kalua‘aha Valley, 12 Jul 1928 (fl., fr.), Degener and Wiebke 3061 (isotypes: BISH, CAS, ILL, K, MASS, NY, RM, US) • Waihānau, 900 m alt., 25 Sep 2008, (fl., fr.), Oppenheimer H 90814 (BISH).</p><p>Peperomia subpetiolata (Fig. 7) is a rare species on East Maui, known only from a small area near and along Olinda Road. This area is just west of the Makawao / Koolau forestry boundary line (Fig. 9). It is a highly distinctive Hawaiian species with leaves 5–8 per node, up to 20 cm long, linear-lanceolate to narrowly elliptic and a spike with a rachis 3.5–4 mm in diameter. Only 11 collections are known and were made in the general area of the Kula Pipeline and Waikamoi Road. No pure individuals of P. subpetiolata have been recorded since the late 1990 s and only putative hybrids have been observed since then, most likely between P. subpetiolata × P. cookiana and / or P. subpetiolata × P. hirtipetiola .</p><p>Peperomia kulensis Yunck. originally described in 1933, based on a single specimen collected from below Kula pipeline on East Maui (G. Munro 800 (BISH)) was treated as a synonym of P. subpetiolata by Wagner et al. (1990, 1999). The features that differed in the type and only collection were included within the description of P. subpetiolata by Wagner et al. (1990, 1999), primarily plant parts hirsute, leaves 9 - to 11 - nerved and the petiole more distinct, but narrowly winged. In 1995, the type was re-examined by Joel Lau and Wagner with the knowledge that P. hirtipetiola C. DC. also grew in those areas and concluded the type was most likely a hybrid and thus annotated the type as a putative hybrid P. subpetiolata × P. hirtipetiola . Since this putative hybrid is now removed from inclusion in P. subpetiolata, a new description is needed and is provided below.</p><p>Description. Herb, terrestrial, stems greenish with reddish-purple splotches, erect to ascending from a very short repent base, not rooting at the nodes, stout, unbranched or 2 - or 3 - branched in upper part, ca. 60–150 cm long, 8–20 mm in diameter, internodes 3–4 cm long or up to 12 cm long in lower part of stem, glabrous. Leaves 5–8 per node, relatively thin, coriaceous, drying chartaceous, linear-lanceolate to narrowly elliptic, 12–20 cm long, 1.5–4 cm wide, palmately 5 - nerved, veins impressed on upper surface, upper surface dark green, lower surface pale green, glabrous, apex long-acuminate, base attenuate, tapering to a short narrowly winged petiole, 0.2–1 cm long. Spikes 1 to 3, terminal and axillary, 8–12 cm long, peduncles ca. 2–3.5 cm long, 3.5–4 mm in diameter, glabrous, flowers densely congested; stamens ellipsoidal, 2; ovary turbinate; stigmas terminal, inconspicuously divided. Fruit subglobose, ca. 1 mm in diameter.</p><p>Specimens of Peperomia subpetiolata examined. USA. Hawaiian Islands, East Maui: • Waikamoi, Kula Pipeline, 5 Sep 1919, Forbes 1283. M (holotype: BISH) • loc. cit., 1372 m alt., 11 Feb 1930, St John 10299 (BISH) • loc. cit., 1250 m alt., 14 Mar 1984, Hobdy 2017 (BISH) • loc. cit., 1250 m alt., 29 Oct 1986, Hobdy 2635 &amp; 2636 (BISH) • loc. cit., 1250 m alt., 14 Mar 1984, Wagner et al. 5675 (BISH).</p></div>	https://treatment.plazi.org/id/6C345A09A9E153078B1B4D7AEC5D749B	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Pensoft via Plazi	Wood, Kenneth R.;Wagner, Warren L.;Fawcett, Susan	Wood, Kenneth R., Wagner, Warren L., Fawcett, Susan (2026): Peperomia kauaiana (Piperaceae), a new alternate-leaved species from Kaua‘i, Hawaiian Islands and notes on two possibly extinct Hawaiian Peperomia. PhytoKeys 269: 113-129, DOI: 10.3897/phytokeys.269.173971
