Achyranthes splendens var. rotundata & var. splendens
Amaranthaceae or Amaranth family
Synonyms for var. rotundata: Achyranthes maneleensis, Achyranthes reflexa, Achyranthes rotundata, Achyranthes splendens var. reflexa
Synonyms for var. splendens: Achyranthes lanaiensis, Achyranthes splendens
No known ancient Hawaiian name
ʻĀhinahina, ‘Ewa hinahina, Hinahina o ‘ewa (see Hawaiian Name below)
Achyranthes, Chaff flower, Round chaff flower, Round-leaf chaff flower, Round-leaved chaff flower
Natural Range & Environment
Achyranthes splendens var. splendens is endemic to Lāna‘i and Maui. It grows in dry shrublands and forests, and on open lava fields and rocky slopes from near sea level to 500 m (1,640 ft) [Flora of the Hawaiian Islands] and possibly higher. It is now field-cultivated on Moloka‘i for seeds used in restoration efforts on Kaho‘olawe (see photograph below).
The endangered Achyranthes splendens var. rotundata is endemic to Oʻahu, Molokaʻi, and Lānaʻi, although it is now likely extinct on Molokaʻi and Lānaʻi [Flora of the Hawaiian Islands]. On O‘ahu, it grows in dry, sunny, coastal areas in Kalaeloa (on calcareous substrate) and near/at Ka‘ena Point (on basaltic substrate) and on dry, shaded cliff faces in very narrow gulches in Mākaha and Wai‘anae Kai Valleys [Joel Lau, Flickr]. It is now being planted as a replacement species for the extinct A. atollensis in the Northwestern Hawaiian Islands (see photograph below).
The estimated number of wild Achyranthes splendens var. rotundata has fluctuated significantly from about 400 plants in 1986 when it was federally listed to more than 1,000 in the 2010s to reportedly less than 100 in 2024 [UFSWS 2024]. It now seems unlikely there will ever be reliable reports on the number of "wild individuals" because of several factors, including (1) the species' relatively short lifespan, (2) its ability to rapidly proliferate in the proper environment with favorable climatic events, (3) irregular and inadequate surveys, (4) numerous mitigation and restoration plantings and translocations, and the establishment of new sites such as at Kahuku on O‘ahu and Mokio on Moloka‘i. Fortunately, thousands of seeds have been collected and stored by both government agencies and private gardens; however, many of these seeds are from cultivated plants of questionable origin [USFWS 2020; USFWS 2024]. Additionally, A. splendens var. rotundata is one of the few endangered native Hawaiian plants that is sometimes available for sale at local garden shops and plant sales.
I (Koebele) have a long personal history with this species. If you are interested in my story and some of its real-life heroes, like Dan Moriarty, Frank Stanton, and Nancy Hoffman, please check out my sister site, www.nativehawaiiangarden.org.
Is USFWS a reliable source of information?
For this website, I (Koebele) have relied heavily on the online reports by the US Fish & Wildlife Service for the histories and status of federally-listed endangered plants in Hawai‘i. I am now wondering whether this may have been a mistake since their reports on Achyranthes splendens var. rotundata, a plant I have a long personal history with, contain some serious errors.
I first became involved with the preservation and restoration of this endangered plant in 1997, and you can read about this personal history on my website, www.nativehawaiiangarden.org. While it’s impossible for me to provide a comprehensive list of the errors in all the USFWS reports on Achyranthes splendens var. rotundata because I lack all the source material needed, I can highlight three disturbing errors I found in the latest 5-Year Review [2024]. Hopefully, this will prompt USFWS (or others) to initiate an investigation of their endangered species reports to determine if report mistakes are a common or rare occurrence.
The three errors are all within the section entitled "Review Analysis: New Status Information."
Currently, there are three recently monitored wild populations on O‘ahu (Kalaeloa Heritage Park, lower Mākaha, and Campbell Industrial Park)... There are four translocated populations on O‘ahu at Kahuku, Ka‘ena Point, Campbell Industrial Park, and the Kalaeloa Unit of the Pearl Harbor National Wildlife Refuge Complex ...
The Achyranthes splendens var. rotundata population within the Kalaeloa Heritage Park IS NOT wild! It was started by Shad Kane, who purchased a plant from Home Depot and planted it in the Park in 2012. This was followed up by later plantings by students from nearby colleges and high schools under my direction. With the care (e.g., watering and weeding) of Shad and other Park caretakers, these plants predictably produced seeds, the seeds sprouted, the seedlings grew, and the population expanded within the Park. A survey by me and an assistant shortly after Shad’s initial planting revealed NO A. splendens var. rotundata within 100 m of the Park's perimeter.
While there have been numerous plantings of Achyranthes splendens var. rotundata within the Kalaeloa Unit of the PHNWRC since 1997, the original small population that Dan Moriarty pointed out to us, and that we began helping (e.g., by removing alien Pluchea), was a wild population. This report makes it sound like the population within the Kalaeloa Unit was created rather than wild and subsequently enhanced.
The above statement also implies that there were/are no wild populations of Achyranthes splendens var. rotundata at or near Ka‘ena Point. I am not the best authority regarding the history of this species at or near Ka‘ena Point, and the people who would know best are William Garnett and Joel Lau. However, it is my understanding that there was/is a small wild population of A. splendens var. rotundata growing on the cliffs above the Wai‘anae-side trail to the Point. The plan was to use seeds from this population to create a new population within the protected areas of the Ka‘ena Point State Park. However, somehow, plants grown from seeds collected from Kalaeloa were planted instead. These plants survived and reproduced (although not as prolifically as those cared for within the Kalaeloa Heritage Park). I do not know the current status of the wild cliff population.
All photographs are of Achyranthes splendens var. rotundata. Wild var. rotundata typically have small, round to oval leaves (photograph courtesy of Dan Clark CC BY-NC 2.0) compared to the larger, more elongate leaves of wild var. splendens (see photo-series below). It's possible to dramatically reduce the growth and size of Achyranthes by confining it to a small pot, as this 2-year-old plant demonstrates. Note the differences between this semi-wild plant, planted as a seedling in the USFWS Kalaeloa Unit without subsequent care (with sky in the background), and a fully cultivated plant. Quite surprisingly, var. rotundata is also found in very narrow gulches in Mākaha and Wai‘anae Kai, O‘ahu, where the plants grow on vertical or nearly vertical cliffs that are shaded for much of the day (photograph courtesy of Joel Lau ©). A. splendens var. rotundata is being planted as a replacement species for the extinct A. atollensis in the Northwestern Hawaiian Islands (photograph courtesy of Forest & Kim Starr CC BY 4.0).
All photographs are of Achyranthes splendens var. splendens. A wild plant growing in the dry lava fields of Kanaio, Maui (photograph courtesy of Forest & Kim Starr CC BY 3.0). Variety splendens typically has more elongated leaves and (possibly) longer flower spikes than var. rotundata (photograph courtesy of Forest & Kim Starr CC BY 3.0). Two types of cultivation: a plant carefully cared for in a decorative landscape and hundreds of plants being grown on Moloka‘i for seed production (photograph courtesy Forest & Kim Starr CC BY 3.0 US). Variety splendens has been used extensively on Kaho‘olawe to stabilize the soil and begin the floral restoration of some of the island's most eroded lands (photograph courtesy of Forest & Kim Starr CC BY 3.0).
Description
Achyranthes splendens is a small to medium-sized shrub that can live more than five years in cultivation but usually less than ten. The morphological differences between the two varieties, rotundata and splendens, are often more visible on wild plants and can be blurred when comparing cultivated plants. These differences are: (1) mature var. splendens can be taller (up to 6 ft [2 m]) than mature var. rotundata (about 3 ft [1 m]); (2) var. rotundata has smaller, round to oval leaves, while var. splendens has larger, obovate (egg-shaped with the widest point near the tip) leaves; and (3) var. rotundata has longer floral sepals (8 to 10.5 mm) and bracteoles (4.5 to 5.3 mm) compared to the sepals (6.5 to 8 mm) and bracteoles (3.5 to 5 mm) of var. splendens [Wagner et al. 1990]. Additionally, while not a strict difference, var. splendens often has longer and straighter flower spikes than var. rotundata. In cultivation, var. rotundata can look more like var. splendens, growing taller than typical wild plants and having larger, less oval leaves.
Both varieties are densely covered with tiny white or clear hairs, often making the entire plant appear silvery, gray, or light green. And wild plants often have thicker leaves than cultivated plants, likely because of more arid conditions.
The flowers of both varieties are tiny, greenish-white, perfect (bisexual), and clustered on a long spike developing at a stem's tip. Wild plants typically develop numerous flowering spikes during the spring and summer, while flowering in cultivated plants seems to be more sporadic. The pollinated flowers develop into small, dry, tan, elongated utricles (single-seeded fruits). Within each utricle is a single cylindrical seed [Seeds of Hawaii; Seeds of Hawaii].
Growth Requirements
General
I (Koebele) have only grown Achyranthes splendens var. rotundata. However, based on conversations with other growers, var. splendens has similar, perhaps identical, growth requirements to its endangered sibling variety.
Achyranthes splendens is a beautiful silvery, easy-to-grow shrub that can provide an accent to the landscape or, if planted en masse, create an informal (i.e., lightly pruned) hedge or screen; space the plants 3 to 4 feet (1 m) apart. It can also be grown as a container plant and adapts quite well to being potbound.
Achyranthes splendens grows best in a site with full sunlight for all or most of the day but can also tolerate partial or light shade; it does poorly in heavily shaded areas. It also does well indoors under LED lamps (see photograph above). Water your plant infrequently but regularly and deeply (e.g., one long watering once a month as opposed to briefly watering daily); potted plants will need watering more often (i.e., one to three times a week). However, too much water can transform its beautiful silvery foliage to a pale green and can even kill it; Achyranthes does poorly when kept in regions with high rainfall (i.e., more than 50 inches annually). The species doesn't seem to be picky about soil or media type, except that it should drain water quickly. We have grown plants in lava/cinder, calcareous, clay, and organic-dominant soils. Achyranthes can endure high temperatures, severe drought, strong winds, and some salt spray.
In cultivation, Achyranthes splendens grows and matures quickly, and you can expect a 1 to 2 foot (30 to 61 cm) tall plant producing flowers in less than a year. It can also regenerate from its numerous fallen seeds; remove or pot-up these seedlings to prevent crowding. In-the-ground plants rarely (if at all) require fertilizer to keep them looking nice. However, for containerized plants, apply a controlled-release fertilizer with micronutrients every six months or use a foliar organic or inorganic fertilizer diluted to ⅓ to ½ the recommended strength every couple of months.
Cultivated Achyranthes naturally grow into an attractive ball shape, so pruning is usually not needed except to remove the occasional dead branch. Always use a hand-pruner.
While Achyranthes splendens, particularly those in the wild, can live longer than five years, our cultivated plants seem to "burn out" (i.e., senesce and die) around this age. It seems the more you torture them (i.e., little watering and no fertilizer or confining them to a small pot), the slower they grow and the longer they live. Often, no-effort replacements will appear, sprouting from the numerous fallen fruits around the parent plant. However, to be safe, you should collect and store (in your refrigerator) a handful of fruits so you can grow a new plant when needed. It's not necessary to remove the very tiny seeds from their fruits to store or sprout them. Replacement plants can also be easily rooted from cut stems.
Pests and Diseases
Achyranthes splendens can become infested with mealybugs or scale insects. The mealybugs most often tend to cluster at the stem and flower tips, but they can also infest the roots. Scale insects usually attach and attack the stems and leaves. A particularly nasty scale insect is a brown, hard-shelled type (see photograph below) that reproduces rapidly and can kill your plant in just two weeks. Therefore, if you see this scale insect, act quickly and prune away all the infested branches and then treat the remaining plant with horticultural oil and a systemic pesticide. Achyranthes is also susceptible to root-knot nematodes and pathogenic fungi in the soil. Treating these successfully is difficult. Usually, the best "cure" is to find another distant location in your landscape and try again. Finally, don’t confuse the short lifespan of A. splendens with a disease or pest problem. Refer to the Pests & Diseases page for treatments for mealybugs, scale insects, and root-knot nematodes.
In 2017, at the USFWS Kalaeloa Unit, O‘ahu, a highly destructive false powderpost or bostrichid beetle (Amphicerus sp.) was identified as a threat to Achyranthes splendens var. rotundata [SWCA Environmental Consultants 2019]. While we have not seen this beetle attack cultivated A. splendens, it or a similar species does attack and can kill stressed uhiuhi (Mezoneuron kavaiense).
Mealybugs clustered on Achyranthes stem tips and a deadly, unidentified brown scale insect on the stem and leaves.
Uses
Ancient Hawaiian
There is no known ancient Hawaiian name and hence no known ancient use(s) for this species.
Modern
The flower spikes and leaves are sometimes used in lei [Hui Kū Maoli Ola].
Special Features and Information
General
The Amaranth family (Amaranthaceae) is a large family with approximately 2,040 species within about 165 genera, most being herbs or shrubs with a few trees and vines. They are found in tropical to cool-temperate regions, with a few, like spinach (Spinacia oleracea) and beet (Beta vulgaris), being economically important vegetables. While the majority of species in the family use the more common C3 photosynthesis pathway, around 800 species are C4 plants [WikipediA; Amaranthaceae].
In addition to Achyranthes splendens, other native Hawaiian plants in the Amaranth family (Amaranthaceae) include five other endemic species of Achyranthes (one of which is extinct); a possibly now-extinct amaranth (Amaranthus brownii) endemic to Nīhoa; an endangered amaranth last seen in 2014 (Amaranthus pakai); five endemic species of pāpala (Charpentiera spp.); and the endemic ʻāweoweo (Chenopodium oahuense) [Flora of the Hawaiian Islands].
Because they are easy to grow, produce hundreds of fruits annually, and the fruits are food for native birds, both varieties of Achyranthes splendens have been used in flora and fauna restoration projects, with variety splendens being planted on Kaho‘olawe and variety rotundata being planted on the Northwestern Hawaiian Islands (see photographs above).
Hawaiian Name
There is no known ancient Hawaiian name for this species. In modern times the species is often called ʻĀhinahina, which is equivalent to Āhina and Hinahina and means "gray, gray- or white-haired" [Pukui & Elbert 1986]. However, ʻĀhinahina is also the name of some other native Hawaiian plants with silvery leaves, such as the silversword (Argyroxiphium sandwicense) and wormwoods, Artemisia australis and Artemisia mauiensis. The name ʻEwa hinahina or Hinahina o ʻewa, which loosely translates as "the hinahina of the ‘Ewa Plains of O‘ahu," is today commonly used for the endangered variety rotundata. Within this website, we will sometimes use the abbreviated name Achyranthes for both species varieties rather than ʻĀhinahina since this is the name we most commonly hear others using. However, with recent taxonomic changes (e.g., Nototrichium to Achyranthes), this name too is becoming problematic.
Etymology
Achyranthes comes from the Greek words, achyron, meaning "chaff," and anthos, meaning "flower," referring to the chaff-like parts of the flower [Wagner et al. 1990]. The species and variety name, splendens, translates as "gleaming" or "striking," likely referring to the brightness of the leaves, while the variety name, rotundata, means "becoming round" and refers to the nearly round shape of leaves [Gledhill 2008], probably in comparison to the more elongated leaf shape of var. splendens.
BPK