| Sophora chrysophylla | |
|---|---|
 | |
Scientific classification | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Eudicots |
| Clade: | Rosids |
| Order: | Fabales |
| Family: | Fabaceae |
| Subfamily: | Faboideae |
| Genus: | Sophora |
| Species: | S. chrysophylla |
| Binomial name | |
| Sophora chrysophylla | |
| Synonyms | |
Edwardsia chrysophyllaSalisb.[1] | |
Sophora chrysophylla, known asmāmane inHawaiian, is a species offlowering plant in thepea andbean family,Fabaceae, that isendemic toHawaii.[2] It is highlypolymorphic, growing as ashrub ortree, and able to reach a height of 15 m (49 ft) in tree form. Yellowflowers are produced in winter and spring.
S. chrysophylla has ridged golden brown branches. The tree haspinnately compoundleaves with 6 to 10 pairs ofleaflets. Each leaflet is 0.7 to 5 cm (0.28 to 1.97 in) long and 0.3 to 2.3 cm (0.12 to 0.91 in) wide. Leaves are smooth, or with gray or yellowhairs on the underside. The specific name is derived from theGreek words χρυσός (chrysós), meaning "gold," and Φύλλο (phyllo), meaning "leaf." Flowers are found at the bases of leaves or the ends of branches inclusters – that is, they occur in axillary or terminalracemes. Thecorolla is yellow. Thepetal size ranges from 11.5 to 21 mm (0.45 to 0.83 in) long, and 8 to 20 mm (0.31 to 0.79 in) wide.
The tree blooms in winter and spring. The height of the flowering season is in mid-spring.Māmane wood is dense, hard and durable.Seedpods are persistent, and remain on the tree for most of the year. They are twisted, brown to brownish-gray, have four wings and are 2 to 16 cm (0.79 to 6.30 in) long and usually 1.5 cm (0.59 in) wide. Seedpods are tightly constricted around the yellow-orange or brown to grayish-blackseeds, which are 6.35 mm (0.250 in) long. Untreated, the seeds havegermination rates of less than 5%. The tree isperennial and highlypolymorphic.
Māmane is an endemic species of Hawaii, and can be found on allmain islands exceptNiʻihau andKahoʻolawe. It inhabitslow shrublands,high shrublands,dry forests,mixed mesic forests, and, rarely,wet forests.[3] It can grow at elevations of 30–2,900 m (98–9,514 ft), being limited by thetree line.Māmane is most common and grows the tallest in montane dry forests at elevations of 1,220–2,440 m (4,000–8,010 ft).[4]Māmane andnaio (Myoporum sandwicense) define a dry woodlandecotone on thesubalpine areas of EastMaui (Haleakalā) and theIsland of Hawaiʻi.
The hard, durablewood ofmāmane was used by theNative Hawaiians forpou (house posts) andkaola (beams) up to 5 cm (2.0 in) in diameter,ʻōʻō (digging sticks),spears,[5]kope (spades),papa hōlua (sled) runners,papa olonā (Touchardia latifolia scrapers),ʻau koʻi (adze handles), andwahie (firewood).Cattleranchers used it asfence posts.
Inherbal medicine, theflowers are used as anastringent.[6] The wood was also used inreligiousrituals to ward off evil. Akahuna nui (high priest) would wrap a piece ofmāmane wood in a darkkapa cloth and hold it up to symbolize authority.[7]
Sophora chrysophylla contains the alkaloidsMamanine andPohakuline.[8]
Māmane is essential for the endangeredpalila (Loxioides bailleui), which feeds almost exclusively on the plants' immatureseeds when these are in season. It also nests in themāmane branches.Caterpillars ofCydia moths also eat themāmane's seeds, and in turn are eaten by thepalila. Both the bird and the larvae utilize theembryo only, leaving the seed coat untouched.
To other animals,māmane seeds are highly poisonous.House finches die within minutes after eating the seeds. Themāmane employs a two-layered biochemical defence system: The seed coats contain some 4%phenolic compounds, which give them a vile taste. They are also somewhattoxic and have a highfibre content.Seed predators trying to eat the seeds will probably not be killed but at least have a nasty experience. Should a predator be able to penetrate the seed coat, the embryo contains deadly quantities (>4% ofdry weight) ofquinolizidine alkaloids.[9]Thepalila and the moths, however, haveevolved the ability to deal with the poisonous compounds. Thepalila, for example, can deal with dozens of times the dose ofcytisine that would kill alaboratory mouse. Both seed predators seem to be able to recognize and avoid the most poisonous trees.Cydia caterpillars are able to break up the toxic compounds. They do not sequester the alkaloids for their own use, but are found to contain about as much phenolic compounds as the seed coats do. This seems not to be sufficient to deter predators however as they are alsocryptically colored. Thepalila is apparently impervious to the phenolic aroma (as they eatCydia caterpillars which would smell and taste like the plant), discarding the seed coats due to their low nutritional value. How thepalila deals with the toxins is not known.(Bankoet al. 2002)
Feral goats andsheep voraciously eat the seedpods of the plant, negatively impacting the tree'spopulation. Toxicity of the leaves is unknown; it is notable thatUresiphitapolygonalis virescens caterpillars which feed on the leaves haveaposematic coloration. Clearly, this issue requires further study. Ranchcattle can kill trees through stomping on theroots.Wildfire has also destroyed some of the trees, though it is generally resistant to fire, and can grow quickly after one occurs. As regardsdiseases, thecankerascomyceteBotryosphaeriamamane causeswitch's broom disease, which kills heavily-infected trees (Gardner 1997).Māmane grows well in areas where there are no sheep or goats, and cattle populations are limited. The plant is beingreforested in order to increase the population of both the tree itself and thepalila, and revive the indigenous ecosystem.
Media related toSophora chrysophylla at Wikimedia Commons
Data related toSophora chrysophylla at Wikispecies