Viola kauaensis var. hosakae (Violaceae), a new variety of endemic Hawaiian violet.

The Hawaiian endemic Viola kauaensis A. Gray has a broad distribution in bogs of Kaua`i and a limited distribution on mesic ridges in the Ko`olau Mountains of O`ahu. Based on differences in scale, the O`ahu populations of Viola kauaensis had previously been described as a distinct taxon. The taxonomic status of the O`ahu populations was reevaluated through a morphometric analysis of all varieties of Viola kauaensis and the morphologically similar Viola vanroyenii. Morphological features of historic and freshly collected specimens of all varieties of Viola kauaensis were analyzed with a principal components analysis. Populations from O`ahu represent a distinct cluster that slightly overlaps with Viola kauaensis var. kauaensis. Lamina width, apex angle, and base angles contribute to the separation of the O`ahu populations from other varieties of Viola kauaensis. Due to differences in scale, the O`ahu populations are described as Viola kauaensis var. hosakae, a new critically endangered taxon.

Introduction

A. Gray is one of nine species of the monophyletic Hawaiian violets (Violaceae) (Ballard and Sytsma 2000, Havran et al. 2009). The species grows from a creeping rhizome and is notable among endemic Hawaiian in being both herbaceous and bears cleistogamous flowers (Wagner et al. 1999). Two varieties of are recognized: var. kauaensis possesses rotund to cordate PageBreakleaves and is distributed primarily in high elevation bogs and cloud forest margins in central to northwestern Kaua`i (Wagner et al. 1999); var. wahiawaensis Forbes is distributed in the Kanele (Wahiawa) Bog and nearby ridges north of the town of Hanapepe, Kaua`i (Forbes 1920, Wagner et al. 1999). can be differentiated from var. kauaensis by cuneate leaf bases (Forbes 1920, Wagner et al. 1999). While var. kauaensis is locally abundant, var. wahiawaensis is a federally listed endangered taxon.

Additional populations of are located in the Ko`olau Range on the neighboring Hawaiian Island of O`ahu. Individuals in the O`ahu populations resemble var. kauaensis but possess smaller leaves, stipules, flowers, and fruits (St. John 1989). is rare on O`ahu and is distributed on sloping exposed or mossy ground, not in open bogs or forest margins like on Kaua`i. No evidence has been found that the populations on O`ahu produce cleistogamous flowers. Fosberg and Hosaka (1938) mention that “the specimens from O`ahu correspond very well with the dwarf form from the bogs” of Kaua`i. Due to differences in scale, the individuals in the O`ahu populations were named St. John by St. John (1989) in a systematic treatment of all Hawaiian . The O`ahu specimens of were not available for study during the drafting of Manual of the Vascular Plants of Hawai`i (Wagner et al. 1999) and were therefore not treated in that publication. In The Flora of the Hawaiian Islands website, is placed in synonymy with var. kauaensis but W. Wagner noted: “probably this should be treated as a third taxon of ”.

St. John (1989) named one other violet that is morphologically similar to . St. John represents a population of small herbaceous violets endemic to the summit area of Mt. Wai`ale`ale on Kaua`i. One collection was made from the summit by van Royen and Perlman in 1977 (P. van Royen 11733 [BISH]). The population is represented by one herbarium sheet at BISH containing 14 individual plants and several fragments. The species is distributed within the range of var. kauaensis on Kaua`i and has yet to be rediscovered (Ken Wood and Steve Perlman, personal communication).

In the current study, the taxonomic status of O`ahu populations of was reevaluated through an analysis of vegetative and reproductive traits of all varieties of and of . We asked three questions: (1) Is variation in morphological traits discontinuous between interisland populations of ?; (2) Do the O`ahu populations of produce cleistogamous flowers?; and (3) Should the O`ahu populations of be treated as a distinct taxon?

Methods

Field collection

has been documented from several sites on O`ahu. The first recorded collection of the species in 1938 was recorded as “Ko`olau Range, divide between head PageBreakof Kawainui and Kaipapau Gulches” (E.Y. Hosaka 2,504 [BISH]). The site has not been relocated since the original collection. Two additional populations are located in the Poamoho region of the Ko`olau Mountains (due to the rarity of the species, the population locations are referred here as sites A and B). Both locations were visited in May 2013 to make new collections and assess the size of populations.

Site A is located near the Poamoho Trail and contains four small subpopulations. Because the species is considered locally threatened only two whole individuals were collected. One additional flower was collected and preserved in 70% ethanol for dissection. The fragmented nature of the populations and their position on nearly vertical cliff faces (which appears typical for individuals on O`ahu) prevented a random assessment of individuals from the site. To obtain a measure of the size of individuals at Site A, the length and width of the largest lamina of several individuals was measured. A 6 m transect was run parallel to the summit of one ridge. A 2 m tape was extended down the slope of the cliff every 1 m. Individuals easily accessed within 50 cm of the tape were measured.

Site B is located along the Ko`olau Summit Trail. The population was discovered in 1986 by John Obata. Information on the population was shared with Clyde Imada of the Bishop Museum Herbarium (personal communication). The site was revisited by Clyde Imada in 1995 who did not observe any at that time. In May 2013, Site B was revisited to survey for . No individuals of were rediscovered at Site B.

Label data from the type of collected in 1977 (van Royen 11733) indicates that all specimens of were collected from the “summit area of Mt. Wai`ale`ale”. In November 2012, the summit of Mt. Wai`ale`ale was visited by Kyle Kagimoto (The Nature Conservancy of Hawai`i). Five samples of were made from the summit area and are included in the current study.

Measurements

All specimens representing varieties of and on deposit at BISH and DUKE herbaria were analyzed. Digital scans of O`ahu specimens of from PTBG were examined. The type specimens of var. wahiawaensis, , and were analyzed at BISH. A digital scan of the type of from US was analyzed. Five specimens of collected by Kyle Kagimoto were deposited at CAU. Morphological variables measured include: length and width of the leaf lamina, cauline stipules, rhizome stipules, and sepals; length of petioles and capsule valves; and apex and base angles of the leaf lamina. Very few specimens of from O`ahu possessed intact or fully developed petals. Therefore we restricted our floral measurements to sepal characters only. The largest leaf on each specimen was chosen for measurements of foliar characteristics. If a leaf was folded, damaged, or wrinkled to the extent that it could not be determined if it represented the largest leaf, the next largest leaf was chosen for measurement. All size measurements were made to the nearest 0.5 mm. Apex angle was measured as the angle of two rays running along the margins of the leaf tip with the vertex placed just above (at or within 1 mm) of the leaf tip. Base PageBreakangle was measured as the angle of two rays running along the base of the lamia with the vertex placed just below (at or within 1 mm) of the tapered base of the lamina (Ellis et al. 2009). Some specimens of var. kauaensis possessed cordate leaf bases. In these cases, base angle was measured as the angle of two rays running along the inner margins of the left and right portions of the reniform base with a vertex placed at the insertion point of the lamina (Ellis et al. 2009). For one folded leaf of var. wahiawaensis, base angle was estimated based on one half of a folded leaf.

Only one sheet of exists at BISH. The sheet contains 14 individual stems and several fragments. We attempted to measure as many entire samples from this sheet as possible to obtain a robust estimate of morphological variation in the taxon. Only three individuals on the sheet possessed all traits required for a principal components analysis.

Multiple individuals were measured from herbarium sheets when it appeared that vegetative and reproductive structures were attached to separate rhizomes. Digital images of herbarium specimens were used where possible. ImageJ software (Rasband 2012) was used to analyze digital images.

Analyses

A principal component analysis (PCA) was used to investigate the morphological variation between interisland populations and varieties of . The PCA was conducted with varimax rotation on untransformed data. Many herbarium specimens contained samples with degraded, fragmented, missing, or not-otherwise obvious characteristics. Therefore, only specimens that had complete measurements for lamina length, lamina width, petiole length, apex angle, base angle, cauline stipule length, and cauline stipule width were included in the analysis. The 49 samples incorporated into the PCA are listed in Table 1. In accordance with the Kaiser rule, principal component (PC) loadings with eigenvalues above 1.0 were retained for further analysis. Analyses were conducted in R version 2.15.1 (R Core Team 2012).

Table 1.

Samples incorporated into Principal components analysis.

Taxon	Samples per sheet	Island	Collection No.	Herbarium
Viola kauaensis var. hosakae	3	O`ahu	E.Y. Hosaka 2504	BISH
Viola kauaensis var. hosakae	1	O`ahu	E.Y. Hosaka 1927	BISH
Viola kauaensis var. hosakae	1	O`ahu	F.R. Fosberg 13973	BISH
Viola kauaensis var. hosakae	1	O`ahu	F.R. Fosberg 14229	BISH
Viola kauaensis var. hosakae	1	O`ahu	J.C. Havran 2013.4	BISH
Viola kauaensis var. hosakae	1	O`ahu	J.C. Havran 2013.5	BISH
Viola kauaensis var. hosakae	1	O`ahu	S. Perlman 14704	PTBG
Viola kauaensis var. kauaensis	2	Kaua`i	C.N. Forbes 1135K	BISH
Viola kauaensis var. kauaensis	1	Kaua`i	C.J.F. Skottsberg 939	BISH
Viola kauaensis var. kauaensis	1	Kaua`i	J.C.F. Rock 2124	BISH
Viola kauaensis var. kauaensis	1	Kaua`i	J.C.F. Rock 2130	BISH
Viola kauaensis var. kauaensis	1	Kaua`i	C.N. Forbes 906 K	BISH
Viola kauaensis var. kauaensis	1	Kaua`i	D.R. Herbst 2388	BISH
Viola kauaensis var. kauaensis	1	Kaua`i	P. van Royen 11708	BISH
Viola kauaensis var. kauaensis	1	Kaua`i	O. Degener 21747	BISH
Viola kauaensis var. kauaensis	3	Kaua`i	H. St. John 10753	BISH
Viola kauaensis var. kauaensis	1	Kaua`i	C.N. Forbes 406 K	BISH
Viola kauaensis var. kauaensis	1	Kaua`i	J.F.C. Rock 2131	BISH
Viola kauaensis var. kauaensis	1	Kaua`i	O. Degener 21477	BISH
Viola kauaensis var. kauaensis	2	Kaua`i	H. St. John 23038	BISH
Viola kauaensis var. kauaensis	2	Kaua`i	W.N. Takeuchi Alakai_130a	BISH
Viola kauaensis var. kauaensis	1	Kaua`i	P.K. Higashino PKH 9633	BISH
Viola kauaensis var. kauaensis	1	Kaua`i	T.G. Lammers 5382	BISH
Viola kauaensis var. kauaensis	1	Kaua`i	H.F.J. Huber 20	BISH
Viola kauaensis var. kauaensis	1	Kaua`i	W.L. Wagner 5049	BISH
Viola kauaensis var. kauaensis	1	Kaua`i	K. Kajimoto 1	CAU
Viola kauaensis var. kauaensis	1	Kaua`i	K. Kajimoto 2	CAU
Viola kauaensis var. kauaensis	1	Kaua`i	K. Kajimoto 3	CAU
Viola kauaensis var. kauaensis	1	Kaua`i	K. Kajimoto 4	CAU
Viola kauaensis var. kauaensis	1	Kaua`i	K. Kajimoto 5	CAU
Viola kauaensis var. kauaensis	1	Kaua`i	H. St. John 1347	DUKE
Viola kauaensis var. wahiawaensis	1	Kaua`i	H. St. John 10845	BISH
Viola kauaensis var. wahiawaensis	1	Kaua`i	H.U. Stauffer 5911	BISH
Viola kauaensis var. wahiawaensis	1	Kaua`i	D.R. Herbst 2415	BISH
Viola kauaensis var. wahiawaensis	1	Kaua`i	B.C. Stone 1650	BISH
Viola kauaensis var. wahiawaensis	1	Kaua`i	L.H. MacDaniels 606	BISH
Viola kauaensis var. wahiawaensis	2	Kaua`i	C.N. Forbes 166.K (Holotype)	BISH
Viola kauaensis var. wahiawaensis	1	Kaua`i	C.N. Forbes 166.K (Isotype)	BISH
Viola vanroyenii	3	Kaua`i	P. van Royen 11733 (Holotype)	BISH

Floral morphology

Only specimens of var. kauaensis from Kaua`i and var. wahiawaensis possessed open and mature flowers suitable for measuring petals. All specimens of and from O`ahu possessed either cleistogamous flowers or flowers without fully developed petals. St. John (1989) included a three dimensional sketch of a chasmogamous flower and sketches of dissected floral organs in his description of the type of . Due to the degraded nature of the petals in a fragment envelope of the type of at BISH we were unable to reassess size and shape of floral organs from O`ahu. St. John’s (1989) measurements of floral organs from are referenced in discussions of petal size.

Although no individuals with chasmogamous flowers were observed during the 2013 surveys on O`ahu, several unopened flowers were observed. In the field, it was not obvious if the flowers represented unopened chasmogamous flowers PageBreakor fully developed cleistogamous flowers. One flower was collected and preserved in 70% ethanol (multiple flowers were not collected to reduce detrimental impact on the small population). The flower was rehydrated in distilled water prior to dissection. Floral organs were removed and attached to an archival slide. The size and shape of floral organs were compared to Skottsberg’s (1940) illustrations of cleistogamous and chasmogamous floral organs from Kaua`i individuals of .

Results

Field measurements

Site A contained approximately 70 individuals scattered throughout four isolated patches. The violets grow from a layer of exposed moss on heavily sloped areas (Figure 1). All violets in the area had a small stature, less than 5 cm in height above the moss layer. No conspicuous chasmogamous flowers were observed. Lamina dimensions in the field ranged from 2–16 mm in length to 2–15 mm in width. The average leaf lengths and widths were 11 and 11.5 mm, respectively. Despite a thorough search, no individuals of were observed at site B.

Figure 1.

var. hosakae on O`ahu. A Habitat composed of mossy slope B Individual in fruit. (Photo credits: A J. C. H., B Joel Lau).

Data from herbarium specimens show populations from O`ahu possessed consistently smaller mean values of morphological and reproductive traits when compared to populations on Kaua`i (Table 2). Minimum ranges of morphological values from Kaua`i overlap with maximum values from the O`ahu individuals.

Table 2.

Descriptive statistics for select traits quantified for varieties of and . Mean and min-max values are provided. The table includes data from all herbarium specimens analyzed, not just those used for PCA. All measurements in mm.

Trait	Viola kauaensis var. kauaensis (Kaua`i)		Viola kauaensis var. wahiawaensis		Viola kauaensis (O`ahu)		Viola vanroyenii
	mean	min-max	mean	min-max	mean	min-max	mean	min-max
Lamina length	30	11.5–58	36.33	21–52	17.35	8.5–24	6.94	5.5–9
Lamina width	36.37	12.5–77	34.08	14–45	17.27	8–26	8.36	6–11
Petiole length	58.94	9–220	103.17	15–180	33	4–80	8	5–17
Cauline stipule length	7.46	4–14	6.3	3–12	3.18	2–5	3.81	2.5–5
Cauline stipule width	2.75	1.5–5	2.2	1.5–3	1.55	1–2.5	1.62	1–2.5
Sepal length	6.65	5–11	6.86	6–8	4.05	2–6	3.8	3–4.5
Sepal width	2	1–4	1.91	1–3	1.31	0.5–2	1.75	1–3
Capsule valve length	11.1	4.5–17	15	15	7.4	5–9	6.43	5.5–8

The PCA yielded three principal components (PC) with a cumulative proportion of 0.8831 (Table 3). The first two PCs possessed eigenvalues greater than 1.0 and were retained for the construction of a biplot (Figure 2). The biplot depicts overlap between var. wahiawaensis and var. kauaensis. These two varieties are primarily separated along PC2, controlled by apex angle and base angle (Table 2). Individuals of from O`ahu cluster together but overlap slightly with individuals of from Kaua`i. completely overlaps with individuals of from O`ahu. The O`ahu and Kaua`i populations of are primarily separated along PC1, controlled by lamina width (Table 3).

Table 3.

Summary of PCA. Loadings for each variable are presented for the first three Principal Components.

Variable	PC1	PC2	PC3
Lamina length	0.47695396	-0.24381186	0.1296115
Lamina width	0.50188378	0.02178338	0.1166609
Petiole length	0.37770255	-0.23925298	0.5721113
Apex angle	0.08986523	0.61588137	0.4825464
Base angle	0.11415244	0.67522051	-0.1376558
Cauline stipule length	0.40548950	-0.06814306	-0.5148904
Cauline stipule width	0.43867994	0.20727565	-0.3540727
Proportion of variance	0.5362	0.2204	0.1266
Cumulative proportion	0.5362	0.7565	0.8831
Eigenvalue	3.75322839	1.54260388	0.88597604

Figure 2.

PCA Biplot of PC1 and PC2. Symbols: closed squares = var. hosakae; closed triangles = ; open circles = var. kauaensis; open squares = var. wahiawaensis.

Removal of sepals from the preserved flower ( from O`ahu) indicated the presence of several withered petals and only two stamens with anthers. The stamens contained an elongated filament with anthers at their tip. The anther from one of the stamens was in direct contact with the stigmatic surface of the pistil. The style was also relatively short and curved towards the anther. All of these observations were consistent with Skottsberg’s (1940) illustrations of cleistogamous floral organs in specimens from Kaua`i.

Discussion

Herbarium and field data suggest that the herbaceous on O`ahu occupy a much more limited range of morphological variation than var. kauaensis. Individuals in the O`ahu population, like those individuals on Kaua`i, also produce cleistogamous flowers. The individuals on O`ahu demonstrate a fixed range of variation in the size of leaves, petioles, cauline stipules, and flowers. Although not evidenced in the PCA by contribution of base angle along PC1, individuals on O`ahu do not possess the extreme reniform leaf bases often observed in var. kauaensis. This may just be a trait that PageBreakis exaggerated in larger leaves. Due to these variations, the O`ahu individuals are best treated at a distinct infraspecific rank within : var. hosakae.

Recently collected specimens on O`ahu represent a much smaller range of size than those individuals collected early in the 20th century. Leaves of recently collected materials are considerably smaller than those in the type (Figure 3) and represent those individuals more distinct from var. kauaensis in the PCA biplot. has been collected from multiple sites on O`ahu, but is now known from just one population. The variety may have existed across the Ko`olau Mountains in a wide range of sizes, but now persists as a solitary population in the smaller extreme of leaf size. The reduction in range size may be associated with interaction with non-native species. The invasive grass (Raddi) Kuhlm has had a negative impact to summit plants on O`ahu and is found growing alongside var. hosakae. The action of ungulates along the summit area would also detrimentally impact the survivorship of the variety.

Figure 3.

Type of var. hosakae.

The varieties of on Kaua`i and O`ahu occupy different habitats. On Kaua`i var. kauaensis is distributed in the open bog and cloud forest margins of the high-elevation Alakai Swamp. In the bog environments, the species is usually distributed in hummocks of Gaud., mosses, and lichen, while in bog margins the species can be found growing terrestrially or epiphytically in pockets of moss on tree stems. On O`ahu, the one population of var. hosakae contains at least four smaller subpopulations of 4-30 individuals scattered over an area of about 50 m2. Each subpopulation is distributed on a moderate to steeply sloping surface with individuals growing directly out of unsaturated exposed soil or from a thin layer of moss (Figure 1). This microhabitat description differs greatly from the typical habitat of var. kauaensis on Kaua`i (Wagner et al. 1999), especially with regard to the slope.

Havran et al. (2009) and Ballard (2000) included the O`ahu herbaceous violets in their phylogenies of the endemic Hawaiian . In both studies of the Internal Transcribed Spacer (ITS) sequences, the O`ahu populations grouped closely with var. kauaensis. Neither study incorporated material from var. wahiawaensis. The O`ahu individual possessed four differences in the ITS sequence regions compared with the Kaua`i material. The variation is one of the largest seen when comparing interisland populations of conspecifics in the wet clade of Hawaiian violets. var. hosakae likely diverged from var. kauaensis following an interisland dispersal event from Kaua`i to O`ahu.

While it is likely that var. hosakae may have been derived through allopatric speciation, the relationship between and is less clear. falls within the range of morphological variation as var. hosakae, but outside the range of variation of var. kauaensis along PC1. Field observations by Steve Perlman (personal communication) indicate that is sympatric with kauaensis on Kaua`i. may represent var. kauaensis at the smaller extreme of its morphological variation, possibly as a result of harsh conditions at the summit area of Mt Waiale`ale. If more individuals are ever found, this relationship should be reevaluated.

Taxonomic treatment

Havran & Ching Harbin comb. et. stat. nov.

urn:lsid:ipni.org:names:77140439-1

Figure 1B , 3 Additional figures: St. John (1989) Bot. Jarb. Syst. 111(2) 165–204 (Figure 4).

Basionym.

H.St.John, Botanische Jarbücher für Systematik, 111(2), 173, 1989.

Type.

Hawai`i, O`ahu Island, Ko`olau Range, divide between head of Kawainui and Kaipaupau Gulches, rare in bog, 860 m elev., E.Y. Hosaka 2504; July 3, 1938 (holotype: BISH! Sheet no: 72125).

Description.

Rhizomatous herb, rhizome creeping rhizome stipules 1.5–3.0 mm long, 1–2 mm wide, often overlapping and scaly in appearance; vertical stems produced from rhizome, internodes on vertical stem longer than on rhizome, stipules 2.0–5.0 mm long, 1.0–2.5 mm wide. Flowers solitary on terminal peduncle, flower subtended by opposite pair of small linear bracts on peduncles. Chasmogamous flower characteristics as in St. John (1989): dorsal sepal 5 × 1.4 mm, elliptic; lateral sepal 4.5 × 1.4 mm, obovate elliptic; ventral sepal 5.6 × 1.4 mm, lance elliptic; dorsal petals 15 × 3.3 mm, with a 4 mm claw and an elliptic blade; lateral petals 14 × 2.6 mm, with a broad 4 mm claw and an elliptic blade; ventral petal 16 mm long, with a curved 6 mm channeled claw, and an elliptic blade that is 5 mm wide; dorsal stamen 3.9 mm long, filament 0.5 mm long, stout, oblique, anther 2.5 mm long, narrowly obovoid ellipsoid, sterile tip 1.3 mm long, ovate; lateral stamen 3.9 mm long, filament 0.5 mm long and broad, anther 2.3 mm long, narrowly cuneoid, sterile tip 1.3 mm long, ovate, acute; ventral stamen 3.6 mm long, filament 0.5 mm long and wide, anther 2.3 mm long oblanceoloid, sterile tip 1.5 mm long, lanceolate, nectary 1.5 mm high, 0.8 mm wide, arcuate oblong, basal; pistil 2.8 mm long; style 1 mm long; stigma discoid, divergent at 45°; chasmogamous flowers not seen (see methods). Cleistogamous flowers with linear sepals 5, green, 5–6 mm long, 1 mm wide, bases auriculate, apices acuminate, enclosing all other floral organs; petals 5 or fewer, up to 3 mm long, 1 mm wide, white, with withered appearance; stamens 2, 1.5 mm long, filament 1 mm long, anthers 0.5 mm long and at end of filament, anther in direct contact with stigmatic surface of pistil; pistil 2 mm long, ovary 1.5 mm long, style 0.5 mm long, curved at approximately 180˚ towards ovary. Fruit a capsule, capsule valves 7–9 mm long.

Distribution.

Hawaiian Islands, O`ahu: Poamoho summit region of Ko`olau Mountains.

Specimens Examined.

Hawaiian Islands: O`ahu: Laie, 19 Dec 1937, Hosaka 1927 (BISH); Main divide, crest of Ko`olau Mts, above Kaipapau Gulch, 31 May 1937, Fosberg 13973 (BISH); Main divide, crest of Ko`olau Mts, above Kaipapau Gulch, 24 Jul 1937, Fosberg 14229 (BISH); About one half mile south of Poamoho trail along the Ko`olau Summit trail, 20 May 2013,Havran 2013.4 (BISH); About PageBreakPageBreakone half mile south of Poamoho trail along the Ko`olau Summit trail, 20 May 2013, Havran 2013.5 (BISH); Ko`olau Mt summit, on small hill at Puu Pauau, between Poamoho and Schofield-Waikane trail, on west side of Summit trail, about 50 ft. from trail, 12 Mar 1995, Perlman 14704 (PTBG); Ko`olau Mts. Between summit of Poamoho trail and Schofield trail, along summit crest on small hill, about 0.5 miles south of cabin, 7 Sep 1987, Perlman 6456 (PTBG).

Conservation status.

var. hosakae appears very rare on O`ahu. Despite frequent and thorough conservation work by multiple organizations in the summit area of the Ko`olau Mountains, only one population of the variety is known to exist. The population is threatened by grazing ungulates. In addition, island tropical montane environments, like the ones harboring var. hosakae, are incredibly susceptible to global climate change (Loope and Giambelluca 1998).

var. hosakae is best classified as Critically Endangered (CR) according to the IUCN Red List Criteria as it meets the following criteria: B. Area of occupancy less than 10 km2, number of populations = 1, and continuing decline inferred from extent of occurrence and area of occupancy as indicated from herbarium records and personal communication; C. Number of mature individuals less than 250 and an estimated continuing decline (C2) with less than 50 mature individuals in each subpopulation (C2i).

The Plant Extinction Prevention Program (PEPP) branch on O`ahu will work to preserve this taxon on by collecting and germinating seeds when possible. Efforts are underway to enclose the population within an ungulate fence by the end of 2014. An additional population can be started with propagules from the extant population. The cleistogamous reproduction of the variety should help to facilitate seed production in the absence of pollinators at a new location.

1	Leaf base cuneate	Viola kauaensis var. wahiawaensis
–	Leaf base truncate to cordate	2
2	Leaf base truncate to deeply cordate; lamina 13 – 77 mm wide, generally widest in 7 third of lamina, sepals 5-11 mm long; stipules subulate to lanceolate, margins sparsely serrate	Viola kauaensis var. kauaensis
–	Leaf base rounded, truncate, or shallowly cordate; lamina 8-26 mm wide, generally widest in middle of lamina, sepals 2–6 mm long; stipules linear to lanceolate, margins dentate to erose	Viola kauaensis var. hosakae