Cycas micronesica

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Cycas micronesica
Cycas micronesica photo courtesy A. Gawel (15391498081).jpg
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Plantae
Clade: Tracheophytes
Clade: Gymnospermae
Division: Cycadophyta
Class: Cycadopsida
Order: Cycadales
Family: Cycadaceae
Genus: Cycas
Species:
C. micronesica
Binomial name
Cycas micronesica
K.D. Hill, 1994

Cycas micronesica is a species of cycad found on the island of Yap in Micronesia, the Marianas islands of Guam and Rota, and The Republic of Palau. It is commonly known as federico nut or fadang in Chamorro. The species, previously lumped with Cycas rumphii and Cycas circinalis , was described in 1994 by Ken Hill. [2] Paleoecological studies have determined that C. micronesica has been present on the island of Guam for about 9,000 years. [3] It is linked with Lytico-Bodig disease, a condition similar to amyotrophic lateral sclerosis (ALS), due to the neurotoxin BMAA found in its seeds, which were a traditional food source on Guam until the 1960s. [4] The neurotoxin is present due to its symbiosis with cyanobacteria. [5] [6]

Contents

Description

Cycas micronesica is a medium-sized tree most commonly 2–5 meters tall but can reach heights up to 15 meters. The tree has a straight palm like trunk ringed with frond scars. [7]

Leaves

Leaves are 140–180 cm long, flat in section (opposing pinnae inserted at 180 degrees on rhachis), with 130 -150 pinnae, terminated by a spine c. 4mm long; petiole usually glabrous, usually unarmed, rarely spinescent for up to 20% of length, 35 – 45 cm long; median pinnae at 70-80 degrees to rachis, 240 – 280 mm long, 16 –17 mm wide, 0.35 - 0.45 mm thick, glabrous, dull green or slightly bluish-green when developing, becoming glossy mid-green at maturity, flat in section with slightly recurved margins, strongly discolorous, decurrent for 7–10 mm, narrowed to 5.0-6.0 mm at base, 17 – 20 mm apart on rhachis apex attenuate; midrib not sharply raised, more or less equally prominent above and below, 1.2 -1.5 mm wide. [8]

Reproductive organs

Like all cycads, Cycas micronesica are dioecious. Females possess clusters of ovules situated on modified leaves called megasporophylls. Male reproductive structures consist of modified leaves called microsporophylls, but each modified leaf has small, compact pollen sacks attached to their lower surface. [9] There has been documentation of the symbiotic relationship the Guamanian C. micronesica with Anatrachyntis sp., which depends on male cones (microsporangia) for oviposition and recruitment in return for pollinating the species.

The microsporangiate cones are pale fawn to pale orange-brown, narrowly ovoid, 30–50 cm long, 8–10 cm in diameter. Microsporophyll lamina are 35–45 mm long, 20–25 mm wide; fertile zone 25–35 mm long; sterile apex 7–10 mm long, not recurved, apical spine somewhat reduced, broad, sharply upturned, 2 mm long. Megasporophylls 27–33 cm long, grey- and orange-tomentose, with 2-6 ovules, lamina 45–55 mm wide, broadly ovate to elliptical, regularly dentate with 16-20 lateral spines, apical spine 8–15 mm long, lateral spines 2–6 mm long. Seeds flatten to ovoid, green becoming orange, not pruinose, 50–60 mm long, 45–50 mm in diameter; sarcotesta 3–6 mm thick. [8]

Conservation

Cycas micronesica is threatened by a combination of introduced species throughout the islands of Guam and Rota. The most notable pest is the diaspidid scale Aulacaspis yasumatsui , which was first recognized in Guam in December 2003. [10] Other threats include cycad blue butterfly ( Luthrodes pandava ), the longhorn beetle ( Acalolepta marianarum ) which causes stem damage, the alien invasive snail Satsuma mercatoria which feeds on young leaflets, and habitat loss due to the growing human population. [1] Prior to the invasion of Aulacaspis yasumatsui, it was one of the most abundant plants in Guam's forests. [11] Plant mortality was so rapid that the species was Red Listed as Endangered in 2006, only three years after the devastating invasions began. [12] [13] Population counts in northwest Guam have declined from 686 individuals in early 2004 (before Aulacaspis yasumatsui reached this habitat) to 87 individuals in January 2007. [1] In 2004, Rhyzobius lophanthae was employed on Guam as a biological pest control and has lessened the population decline. However, they were ineffective on protecting cycad seedlings from Aulacaspis yasumatsui predation, as lack of seed vigor is one of the major factors contributing to C. micronesica decline. [14] without effective action against the Aulacaspis scale, it may become critically endangered. It used to have stable populations across Micronesia, with Guam having the largest. However, the Aulacaspis scale invasion caused an 87% decline in the Guam subpopulation over ten years. [15]

Threats

The Cycad Aulacaspis scale, an invasive species from Southeast Asia, poses a significant threat to Cycas micronesica, resulting in substantial plant mortality. However, it's crucial to emphasize that the current plant mortality is not solely due to this scale. The introduction of the Cycad Blue Butterfly in 2005 and the intensified damage caused by pre-existing arthropod pests are additional severe threats to the already weakened cycad population. Longhorn beetles, especially Acalolepta marianarum, are responsible for many recent plant deaths due to stem damage. Moreover, the invasive snail Satsuma mercatoria has emerged as a new and significant threat by feeding on young leaflets. This change in herbivore behavior may be a result of the compromised ability of unhealthy cycad plants to synthesize chemicals that deter herbivores. These threats collectively imperil the survival of Cycas micronesica. [15]

See also

Related Research Articles

<span class="mw-page-title-main">Sporangium</span> Enclosure in which spores are formed

A sporangium ; pl.: sporangia) is an enclosure in which spores are formed. It can be composed of a single cell or can be multicellular. Virtually all plants, fungi, and many other lineages form sporangia at some point in their life cycle. Sporangia can produce spores by mitosis, but in nearly all land plants and many fungi, sporangia are the site of meiosis and produce genetically distinct haploid spores.

<span class="mw-page-title-main">Cycad</span> Division of naked seeded dioecious plants

Cycads are seed plants that typically have a stout and woody (ligneous) trunk with a crown of large, hard, stiff, evergreen and (usually) pinnate leaves. The species are dioecious, that is, individual plants of a species are either male or female. Cycads vary in size from having trunks only a few centimeters to several meters tall. They typically grow very slowly and live very long. Because of their superficial resemblance, they are sometimes mistaken for palms or ferns, but they are not closely related to either group.

<i>Stangeria</i> Monotypic genus of cycads in the family Stangeriaceae

Stangeria eriopus is a cycad endemic to southern Africa. It is the sole species in the genus Stangeria, most closely related to the Australian genus Bowenia, with which it forms the family Stangeriaceae.

<i>Cycas</i> Genus of cycads in the family Cycadaceae

Cycas is a genus of cycad, and the only genus in the family Cycadaceae. About 113 species are accepted, which are native to the Indo-Pacific, East Africa and Madagascar. Cycas circinalis, a species endemic to India, was the first cycad species to be described in western literature, and is the type species of the genus. The best-known Cycas species is Cycas revoluta.

<i>Cycas revoluta</i> Species of plant

Cycas revoluta is a species of gymnosperm in the family Cycadaceae, native to southern Japan including the Ryukyu Islands. It is one of several species used for the production of sago, as well as an ornamental plant. The sago cycad can be distinguished by a thick coat of fibers on its trunk. The sago cycad is sometimes mistakenly thought to be a palm, although the only similarity between the two is that they look similar and both produce seeds.

<span class="mw-page-title-main">Sporophyll</span>

A sporophyll is a leaf that bears sporangia. Both microphylls and megaphylls can be sporophylls. In heterosporous plants, sporophylls bear either megasporangia and thus are called megasporophylls, or microsporangia and are called microsporophylls. The overlap of the prefixes and roots makes these terms a particularly confusing subset of botanical nomenclature.

<i>Dioon</i> Genus of cycads in the family Zamiaceae

Dioon is a genus of cycads in the family Zamiaceae. It is native to Mexico and Central America. Their habitats include tropical forests, pine-oak forest, and dry hillsides, canyons and coastal dunes.

A strobilus is a structure present on many land plant species consisting of sporangia-bearing structures densely aggregated along a stem. Strobili are often called cones, but some botanists restrict the use of the term cone to the woody seed strobili of conifers. Strobili are characterized by a central axis surrounded by spirally arranged or decussate structures that may be modified leaves or modified stems.

<i>Cycas angulata</i> Species of cycad

Cycas angulata is a species of cycad in the genus Cycas, native to Australia in northeast Northern Territory and northwest Queensland.

<i>Cycas beddomei</i> Species of cycad

Cycas beddomei is a species of cycad in the genus Cycas, native to India, where it is confined to a small area of Andhra Pradesh state in the Tirumala Hills in scrubland and brush covered hills.

<i>Cycas bougainvilleana</i> Species of cycad

Cycas bougainvilleana is a species of cycad in the genus Cycas, native to the islands northeast of Papua New Guinea, on New Britain, the Bismarck Archipelago and the Solomon Islands, where it occurs on or near the coast in calcareous coral sand dunes and in adjacent forests.

Lytico-bodig (also Lytigo-bodig) disease, Guam disease, or amyotrophic lateral sclerosis-parkinsonism-dementia (ALS-PDC) is a neurodegenerative disease of uncertain etiology endemic to the Chamorro people of the island of Guam in Micronesia. Lytigo and bodig are Chamorro language words for two different manifestations of the same condition. ALS-PDC, a term coined by Asao Hirano and colleagues in 1961, reflects its resemblance to amyotrophic lateral sclerosis (ALS), Parkinson's disease, and Alzheimer's disease.

β-Methylamino-<small>L</small>-alanine Chemical compound

β-Methylamino-L-alanine, or BMAA, is a non-proteinogenic amino acid produced by cyanobacteria. BMAA is a neurotoxin. Its potential role in various neurodegenerative disorders is the subject of scientific research.

<i>Cycas circinalis</i> Species of cycad

Cycas circinalis, also known as the queen sago, is a species of cycad known in the wild only from southern India. Cycas circinalis is the only gymnosperm species found among native Sri Lankan flora.

<i>Macrozamia glaucophylla</i> Species of plant

Macrozamia glaucophylla is a species of cycad from the genus Macrozamia and the family Zamiaceae. Endemic to New South Wales, Australia, this species has features that resembles palms, although both species are taxonomically quite different. The current population trend of Macrozamia glaucophylla is stable with 2,500 to 10,000 mature individuals. The species are found in several habitats including forest and savanna. Ecologically, Macrozamia glaucophylla lives in terrestrial system, a land-based community of organisms where the biotic and abiotic components interact in the given area.

<i>Cycas pectinata</i> Species of cycad

Cycas pectinata was the fourth species of Cycas to be named; it was described in 1826 by Scottish surgeon and botanist Francis Buchanan-Hamilton from Kamrup, Assam in northeast India. The species is one of the most widespread cycads. It is found in the northeastern part of India, Nepal, Bhutan, northern Burma, southern China (Yunnan), Bangladesh, Burma, Malaysia, Cambodia, northern Thailand, Laos, and Vietnam. Cycas pectinata usually grow at elevation 300 m to 1200 m and in difficult terrains. In China, it grows in dry, open thickets in limestone mountains, red soil in sparse monsoon forests. Cycas pectinata grows up to 40 feet (12 m) tall and has very large, ovoid male cones. The tallest Cycas pectinata is a female plant in North Kamrup, Assam which measures 52.8 feet (16.1 m). The tree is the world's tallest Cycas plant. In Northeast India, the species is under severe threat due to clearing of forest and overcollection of male cones for preparation of traditional medicines. The species is listed in CITES Appendix II and IUCN Redlist.

<i>Cycas rumphii</i> Species of plant

Cycas rumphii, commonly known as queen sago or the queen sago palm, is a dioecious gymnosperm, a species of cycad in the genus Cycas native to Indonesia, New Guinea and Christmas Island. Although palm-like in appearance, it is not a palm.

<i>Cycas thouarsii</i> Species of evergreen plant

Cycas thouarsii, the Madagascar cycad, is an evergreen arborescent cycad in the genus Cycas. It is named after a French botanist Louis-Marie Aubert du Petit-Thouars (1758—1831).

<span class="mw-page-title-main">Aulacaspis yasumatsui</span> Species of true bug

Aulacaspis yasumatsui, or cycad aulacaspis scale (CAS), is a scale insect species in the genus Aulacaspis that feeds on cycad species such as Cycas revoluta or Dioon purpusii. Other common names include the cycad scale, the sago palm scale, and the Asian cycad scale. This is a serious pest of cycads which can kill its host plant.

<i>Cycas inermis</i> Species of cycad

Cycas inermis is a vascular plant belonging to the family Cycadaceae, endemic to central and southern Vietnam. Its name in Vietnamese is Thiên tuế or Tuế lá quyết.

References

  1. 1 2 3 Bösenberg, J.D. (2022). "Cycas micronesica". IUCN Red List of Threatened Species . 2022: e.T61316A68906033. doi: 10.2305/IUCN.UK.2022-1.RLTS.T61316A68906033.en . Retrieved 22 August 2023.
  2. ↑ Hill, K.D. (1994). Cycas micronesica. Australian Systematic Botany7: 554-556.
  3. ↑ Athens, J., & Ward, J. (2004). Holocene vegetation, savanna origins and human settlement of Guam. Records Of The Australian Museum, 15-30.
  4. ↑ Sacks, Oliver. (1996). The Island of the Colour-blind. Pan Macmillan Australia: Sydney. ISBN   0-330-35887-1
  5. ↑ Cox PA, Banack SA, Murch SJ, Rasmussen U, Tien G, Bidigare RR, Metcalf JS, Morrison LF, Codd GA, Bergman B (2005). "Diverse taxa of cyanobacteria produce b-N-methylamino-L-alanine, a neurotoxic amino acid". PNAS. 102 (14): 5074–5078. Bibcode:2005PNAS..102.5074C. doi: 10.1073/pnas.0501526102 . PMC   555964 . PMID   15809446.
  6. ↑ Esterhuizen M, Downing TG (2008). "β-N-methylamino-L-alanine (BMAA) in novel South African cyanobacterial isolates". Ecotoxicology and Environmental Safety. 71 (2): 309–313. doi:10.1016/j.ecoenv.2008.04.010. PMID   18538391.
  7. ↑ Vogt, S., & Williams, L. (2004). Common flora & fauna of the Mariana Islands. Saipan?: S.R. Vogt & L.L. Williams.
  8. 1 2 Hill KD (1994). "The Cycas rumphii complex (Cycadaceae) in New Guinea and the western Pacific". Australian Systematic Botany. 7 (6): 543–567. doi:10.1071/sb9940543. ISSN   1446-5701.
  9. ↑ Willis, K., & McElwain, J. C. (2014). The evolution of plants (2nd ed.). Oxford, United Kingdom; New York: Oxford University Press.
  10. ↑ Terry, Irene; & Marler, Thomas. (2005). Paradise Lost? Tipping the scales against Guam’s Cycas micronesica. The Cycad Newsletter28(3-4): 21-23.
  11. ↑ Donnegan, J., & Pacific Northwest Research Station. (2004). Guam's forest resources, 2002 (Resource bulletin PNW ; 243). Portland, OR: U.S. Dept. of Agriculture, Forest Service, Pacific Northwest Research Station.
  12. ↑ Marler, T.E.; Lawrence, J.H. (2012). "Demography of Cycas micronesica on Guam following introduction of the armoured scale Aulacaspis yasumatsui". Journal of Tropical Ecology. 28 (3): 233–242. doi:10.1017/S0266467412000119.
  13. ↑ Marler, T.E. (2010). "Cycad mutualist offers more than pollen transport". American Journal of Botany. 97 (5): 841–845. JSTOR   20700414.
  14. ↑ Marler, T.E.; Miller, R.; Moore, A. (2013). "Vertical Stratification of Predation on Aulacaspis yasumatsui Infesting Cycas micronesica Seedlings". HortScience. 48 (1): 60–62. doi: 10.21273/HORTSCI.48.1.60 .
  15. 1 2 "Redlist - Cycas micronesica".

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