Cyanea konahuanuiensis Sporck-Koehler, M. Waite & A.M. Williams, 2015

Sporck-Koehler, Margaret J., Koehler, Tobias B., Marquez, Sebastian N., Waite, Mashuri & Williams, Adam M., 2015, A new species of Cyanea (Campanulaceae, Lobelioideae), from the Ko'olau Mountains of O'ahu, Hawaiian Islands, PhytoKeys 46, pp. 45-60 : 48-54

Cyanea konahuanuiensis Sporck-Koehler, M. Waite & A.M. Williams sp. nov. Figures 3, 4, 5, 6, 7

Note.

Species believed to be allied to Cyanea humboldtiana (Gaudich.) Lammers, Givnish & Sytsma, but primarily differs in its longer calyx lobes (16-18 mm long); and its more densely pubescent leaves, petioles, flowers, and differing flowering period. Cyanea humboldtiana has leaves, petioles, and flowers that are more sparsely pubescent with shorter trichomes; leaf margins are callose-crenulate, floral bracts have acute apices, and its calyx lobes are ovate, acuminate and considerably shorter (4-10 mm long). The two species are reproductively isolated from each other due to lack of overlapping flowering periods ( Cyanea konahuanuiensis flowers from June-August and Cyanea humboldtiana from October-December), and they are not known to intergrade.

Type.

USA, Hawai‘i, O‘ahu Island, Ko‘olau Range: Kōnāhua-nui, near summit, 912m (2991 ft), 9 July 2013, M. Sporck, T. Koehler, & M. Waite MJS 0019 (holotype: BISH 1049136), (Figure 9).

Description.

Unarmed shrubs 57-69 cm high, with 1-6 stems originating at the base; stems light green and darkening to a light brownish gray closer to the base, erect to decumbent, 58-119 cm in length, some branches partially resting on the ground, occasionally rooting when in contact with the soil or moss producing aerial roots, leaf scars subcircular, 9.5-12 × 6.5-11.8 mm, upper end of leaf scar depressed, basal portion slightly raised; leaf scar with a protuberance; latex white. Leaves clustered distally near end of stems, petiolate; petioles 2-4.2 cm long, pubescent; blades elliptic to oblong, in adult plants 20-33 × 10-16 cm, base cuneate to rounded, occasionally slightly truncate, apex acute to sub-obtuse, margins serrate to serrate-dentate, dull grayish-green on adaxial surface and dull greenish white on abaxial surface, stiff, slightly fleshy, both surfaces densely hirsute and minutely muricate; in juvenile plants leaves are less stiff, margins dentate, and hairs softer. Inflorescences axillary just above the leaf, up to 4 per stem, young inflorescences roughly perpendicular to stem, larger and more developed inflorescences pendant, 3-12 flowered, peduncles 5-12.2 cm long (dried specimen 7.7 cm long), pubescent. Flowers on pedicels 7-14 mm long (5-10 mm when dried), pubescent, subtended by linear bracts 7-18 × 2-6 mm, apex obtuse, margins entire, densely pubescent; hypanthium 10-15 mm (9-14 mm when dried) × 7-10 mm (5-7 mm when dried), obovoid to cylindrical, pubescent; calyx lobes linear to linear-oblong,16-18 × 5-7 mm (13-17 × 3-5 mm when dried), apex acute to subobtuse, retained on immature (green) fruits (no mature fruit seen); corolla dark purple with some lighter streaks developing with age, tubular, laterally compressed, curved, 86-99 mm long (80-95 mm when dried) × 12-13 mm wide medially (9-12 mm when dried), externally densely pubescent, internally glabrous, the lobes linear-subulate, 10-16 mm long × 5 mm wide at the base, reflexed, c. 1/4-1/3 as long as the tube; staminal column glabrous, adnate to corolla for half its length, anthers 9-10 mm long, scantily pubescent, the lower two with apical tufts of white hairs 2-3 mm long. Fruits berries (mature fruits not seen), immature fruits densely pubescent, with calyx lobes persistent. Seeds from immature fruits numerous, embedded in green pulp, obovoid, 0.74-0.84 × 0.58-0.64 mm, testa medium to dark brown, shiny and smooth.

Distribution.

Known only from the Kōnāhua-nui summit area in the Ko‘olau Mountains of O‘ahu, Hawaiian Islands. The population is on land owned by the State of Hawai‘i, Department of Land and Natural Resources (DLNR), and is part of the Honolulu Watershed Forest Reserve (Figure 1).

Habitat and ecology.

Cyanea konahuanuiensis occurs in wet forest sites at elevations from 884 to 932 m. The associated native Hawaiian plant species include Broussaisia arguta Gaudich., Cheirodendron platyphylla (Hook & Arn.) Seem., Dubautia laxa (Hook. & Arn.) Machaerina angustifolia (Gaudich.) T. Koyama, Metrosideros rugosa A. Gray, Perrotettia sandwicensis A. Gray, Phyllostegia grandiflora (Gaudich.) Benth., Polyscias gymnocarpa (Hillebr.) Lowry & G. M. Plunkett, Sadleria pallida Hook. & Arn., Scaevola mollis Hook. & Arn., and species of Cibotium Kaulf., Kadua Cham. & Schltdl., Labordia Gaud., Melicope J.R. Forst. & G. Forst., and Wikstroemia Endl. Introduced naturalized plant species include: Ageratina adenophora (Spreng.) R.M. King & H. Rob., Clidemia hirta (L.) D. Don, Hedychium gardnerianum Sheppard ex Ker Gawl., Rubus rosifolius Sm., and Setaria palmifolia (J. König) Stapf. Bryophyte species are prevalent and include Distichophyllum freycinetii ( Schwägr.) Mitt., Plagiochila diflexa Mont. & Gottsche, and species of Bazzania S. Gray. The native arthropod, Megalagrion oahuense Blackburn (a Hawaiian endemic damselfly) has been observed on Cyanea konahuanuiensis . Soil is of basaltic origin and typical of wet forest sites on O‘ahu and the average annual rainfall is approximately 2600 mm ( Giambelluca et al. 2013). The plants occupy a gulch both at the base and middle of relatively steep slopes which results in direct sunlight exposure occurring for a few hours close to midday and varying seasonally. Plants occur on both northwest and south facing slopes of the gulch, mostly along the banks of intermittent streams, but can also be found several meters from the stream with no apparent preference. Small stem fragments that are detached from plant have been observed to take root, forming new clones.

Phenology.

Cyanea konahuanuiensis has been observed flowering from June-August with fruit developing from August-October. All observed fruits have aborted, been eaten, or decomposed before maturity. The lifespan and time to maturity of the species is unknown. Immature, nearly aborted fruits have been collected when all others had aborted. Fruits have been submitted to the Lyon Arboretum Micropropagation lab where some of the seeds have germinated and it is interesting to note that the seedlings have densely pubescent leaves (Figure 3).

Etymology.

The specific name pays homage to the twin-peaked (946 m and 960 m) Kōnāhua-nui Pu‘u (summit), the tallest peaks in the Ko‘olau Mountain range on windward (east) O‘ahu. Lit. Large fat innards ( Pukui et al. 1974), + Latin suffix - ensis, indicating a place of origin or belonging. "In one story a giant threw his great testicles (Kona hua nui) at a woman who escaped him." ( Pukui et al. 1974). Kōnāhua-nui has significance not only because it is the highest peak in the Ko‘olau Range, but because the summit area is a largely intact native ecosystem in relative close proximity to Honolulu, the largest city in the State of Hawai‘i. To our knowledge, there has never before been a plant species named after this beautiful and biologically important locality. After seeking counsel with Hawaiian cultural practitioners Kaua Neumann and Kīhei Nahale-a (pers. comm. 2014), it is proposed to give the species a Hawaiian name of Hāhā mili‘ohu, meaning "The Cyanea that is caressed by the mist".

Conservation.

Cyanea konahuanuiensis is a critically imperiled species (see Conservation status below) due to its low population numbers and exceptionally narrow endemism. Some of the conservation obstacles to overcome include probable loss of most, if not all, of its native avian pollinators and dispersers, and suspected herbivory by introduced taxa such as rats, terrestrial gastropod mollusks (slugs), and feral pigs ( Sus scrofa ). Invasive plant species are becoming increasingly common even in relatively hard to access sites along and near mountain summits in Hawai‘i. Species such as Ageratina adenophora , Clidemia hirta , Erigeron karvinskianus , Hedychium gardnerianum , Rubus rosifolius and Setaria palmifolia are competing with Cyanea konahuanuiensis and other native species for space and resources. It is conceivable that stochastic events such as landslides, hurricanes, and flash-flooding could obliterate the majority or all of the currently known plants with a single event. Approximately 20 mature plants and several immature plants have been observed in total. Plants that were observed ranged from seedlings to reproductively mature individuals. Seedlings are scarce, however, which suggests that the population may be declining.

The Hawai‘i DLNR, Division of Forestry and Wildlife (DOFAW) has largely funded this research by providing staff time to further investigate this species. The Hawai‘i Plant Extinction Prevention (PEP) Program focuses on conserving and restoring plants with less than 50 known wild individuals. Because Cyanea konahuanuiensis falls within that threshold, O‘ahu PEP is working closely with DOFAW staff to protect this critically rare taxon. The first goal of the PEP Program is to secure seeds or propagules from each individual mature plant for ex situ germplasm banking. The long-term goal for the PEP Program and DOFAW will be to collaborate in the effort to grow and out-plant nursery stock into appropriate restoration sites. Currently there are no protected (fenced) areas in similar habitat with comparable elevation, rainfall, humidity, and species composition on O‘ahu. Our recommendation is that additional fenced out-planting sites be established in appropriate areas of the Ko‘olau Mountains in order to establish multiple populations of this species. The authors emphasize the importance of prioritizing staff time to carry out further vegetation surveys in areas that have not been explored in recent history as this exciting new find shows that even seemingly well botanized areas in Hawai‘i may yet yield new discoveries.

In October 2013, immature fruits from two plants were collected and have since germinated at the UH Harold L. Lyon Arboretum after being directly sown on an agar medium. This is valuable information since at this time all observed fruits seem to be aborting prior to maturity. We recommend collecting immature fruit (or mature fruit if possible) from all reproductive individuals during future fruiting seasons in order to secure genetic representation from all reproductively mature individuals in ex situ collections.

The use of cellular phone-connected game cameras is recommended for monitoring of rare plants in remote locations. This novel use of game camera technology saved time and resources, optimizing the timing of visits and increasing the likelihood of making successful and representative observations required for the species description and fruit collections. This rapidly improving technology could have many positive impacts on monitoring rare plants for flower development, fruit development, herbivory impacts, and the effects of various seasonal events.

Specimens examined.

USA. Hawaiian Islands O‘ahu [East O‘ahu]: Paratypes: dried herbarium specimen BISH 1049144; and spirit collections: BISH 1059013, BISH 1059014, and BISH 1059015.

Discussion.

For over a century the taxa that currently comprise the genus Cyanea were recognized as two separate genera, Cyanea and Rollandia . The genus Rollandia was distinguished from Cyanea based on the single character of staminal column adnation to corolla in the former ( Gaudichaud-Beaupré 1844; Hillebrand 1888; Lammers 1990; Rock 1919). Phylogenetic investigations of molecular data revealed that the taxa of Rollandia are embedded within the genus Cyanea (Lammers, 1993). Together with two species of Cyanea ( Cyanea acuminata and Cyanea grimesiana ), they form a clade referred to as the " acuminata clade" ( Givnish et al. 1995). Cyanea konahuanuiensis most likely belongs in this clade based on the staminal column being adnate to the corolla tube. It is noteworthy to mention that Cyanea konahuanuiensis shares close geographic proximity to several taxa of the acuminata clade. Eight out of the nine previously recognized Rollandia taxa from this clade are endemic to O‘ahu (the ninth taxon, Cyanea parvifolia C. N. Forbes is only known from the type specimen collected on Kaua‘i) and six out of those eight are even more restricted, occurring only in the Ko‘olau Range. Of those six, one taxon ( Cyanea humboldtiana ) is known to occur on the summit ridges near Cyanea konahuanuiensis .