edgepedia

Conifers and other gymnosperms

343 articles

Cycas

Cycas is the sole genus of Cycadaceae, the sister lineage to all other cycads, with about 115 species from East Africa to the western Pacific, a Palaeogene crown age, and rapid Miocene radiations.

Cycas armstrongii

Cycas armstrongii is a fire-adapted cycad endemic to the Top End of Australia's Northern Territory, where dense stands in eucalypt savanna make it one of the world's most abundant cycads.

Cycas cultivation and horticulture

Cycas cultivation is the ornamental growing of Cycas, palm-like cycads including the sago palm (Cycas revoluta). It covers growing conditions, propagation from seed and offsets, pests, and toxicity.

Cycas media

Cycas media is a palm-like cycad of northern and eastern Australia, first described by Robert Brown in 1810, whose toxic seeds were a staple Aboriginal food after detoxification.

Cycas micronesica

Cycas micronesica, known in Chamorro as fadang, is a cycad native to Guam, Rota, Palau, and Yap whose populations collapsed after an invasive scale insect arrived in 2003.

Cycas revoluta

Cycas revoluta (sotetsu, sago cycad, Japanese sago palm) is a slow-growing dioecious cycad native to Fujian, the Ryukyus, Kyushu, Shikoku, and Taiwan; toxic cycasin-containing ornamental gymnosperm, IUCN Least Concern but threatened by the invasive cycad aulacaspis scale.

Cycas thouarsii

Cycas thouarsii is a trunk-forming cycad native to Madagascar, the Comoros, Aldabra, and East African coasts, reaching 10 m tall with distinctly bluish new leaves and buoyant seeds.

Cycasin

Cycasin (methylazoxymethanol beta-D-glucoside) is a carcinogenic, neurotoxic azoxyglycoside from cycads, isolated from Cycas revoluta seeds in 1955; gut bacterial beta-glucosidases release its toxic aglycone MAM.

Cypress canker

Cypress canker, or Seiridium canker, is a fungal disease of Cupressaceae caused mainly by Seiridium cardinale, first described in California in 1928 and now pandemic, especially severe on Italian cypress in the Mediterranean.

Cypress wood and its uses

Cypress wood, from the Mediterranean cypress and related species, resists fungal decay and insects, making it prized for coffins, temples, doors, boats, and furniture since antiquity.

Dacrydium

Dacrydium (Sol. ex Lamb., 1806) is a genus of 21 conifer species in Podocarpaceae from Southeast Asia to New Zealand; once a broad genus, it was split, leaving rimu (D. cupressinum) as its best-known member.

Dacrydium cupressinum

Dacrydium cupressinum, rimu or red pine, is New Zealand's endemic podocarp conifer, a 30-50 m dioecious forest tree reaching 1,000 years, once the country's main native timber, IUCN Least Concern.

Dehydroabietic acid

Dehydroabietic acid (DHAA) is a tricyclic abietane-type diterpene resin acid and major, oxidation-resistant component of rosin, formed as abietic acid aromatizes during aging and during industrial rosin processing.

Dendroctonus frontalis

Dendroctonus frontalis, the southern pine beetle, a 3 mm Scolytinae bark beetle of pines from Honduras to New England; kills hosts via frontalin-driven mass attacks, S-shaped galleries, and fungal symbionts.

Dendroctonus micans

Dendroctonus micans, the great spruce bark beetle (European spruce bark beetle), is a Palaearctic bark beetle pest of spruce from Siberia to Britain, controlled mainly by the specific predator Rhizophagus grandis.

Dendroctonus rufipennis

Dendroctonus rufipennis, the spruce beetle, is a native North American bark beetle killing mature spruce across the continent. Distinguished from Ips typographus and D. ponderosae by its spruce hosts, two-year life cycle, and major Alaska and Yukon outbreaks.

Dioon

Dioon is a genus of 18 accepted cycad species in Zamiaceae, native from Mexico to Honduras. Originating about 56 Ma in eastern Mexico, it includes the slow-growing, ethnobotanically important chamal (Dioon edule).

Dioon edule

Dioon edule, chestnut dioon or chamal, a slow-growing Mexican cycad (Zamiaceae) from the Sierra Madre Oriental; dioecious, beetle-pollinated, over 2500 years lifespan, IUCN Near Threatened, CITES Appendix II, cold-hardy to about -12 °C.

Dioon holmgrenii

Dioon holmgrenii, Palmera de Sol, an endangered Mexican cycad (Zamiaceae) described in 1981, endemic to Pacific-slope pine-oak forest of Oaxaca at 580–850 m, with six genetically isolated populations.

Dothistroma septosporum

Dothistroma septosporum, red band needle blight fungus, primary cause of Dothistroma needle blight of pines; Eurasian origin, worldwide distribution, dothistromin toxin, weather-driven epidemics, major plantation losses.

Douglas fir

Douglas fir (Pseudotsuga menziesii), also called Oregon-pine or Douglas-spruce, is a major western North American timber conifer that is not a true fir; two varieties, coast and Rocky Mountain, range from 19° to 55° N.

Ecology and conservation of cypresses

The ecology and conservation of cypresses concerns small, isolated California stands of fire-adapted conifers whose serotinous cones need fire to open, making fire suppression a conservation threat.

Ecology and conservation of yews (Taxus)

The ecology and conservation of yews covers the genus Taxus, shade-tolerant conifers whose red arils recruit birds as seed dispersers and whose wild populations face browsing, fire, and slow regeneration.

Ecology and habitat of Cycas

The ecology and habitat of Cycas, the largest cycad genus, spans coastal dunes, savanna, rainforest, and limestone karst in the tropics, with insect pollination and fire-tolerant, nitrogen-fixing coralloid roots.

Ecology of coniferous forests

Ecology of coniferous forests is the study of how forests dominated by pines, spruces, firs, and larches initiate, burn, decompose litter, cycle nutrients, and support fungi and soils.

El Palo Alto

El Palo Alto is a famous ~1,000-year-old coast redwood (Sequoia sempervirens) on San Francisquito Creek, California Historical Landmark #2, namesake of Palo Alto; 110 ft tall, down from 162 ft, saved by wells capped and misting.

Encephalartos

Encephalartos (bread trees), African-endemic cycad genus in Zamiaceae with 68 taxa, 85% threatened, dioecious cone-bearing plants pollinated by specialized insects; all species CITES Appendix I.

Encephalartos ferox

Encephalartos ferox, the holly-leafed cycad (Zamiaceae), native Mozambique to KwaZulu-Natal; glossy spiny holly-like leaflets, bright red cones, dioecious, IUCN Near Threatened, CITES Appendix I, about 100,000 mature individuals.

Encephalartos horridus

Encephalartos horridus, the Eastern Cape blue cycad, is an Endangered South African cycad with intense blue foliage, a ~431 km2 range, under 5,000 mature plants, heavy poaching, and CITES Appendix I listing.

Encephalartos woodii

Encephalartos woodii, Wood's cycad, a South African cycad from Ngoye Forest, KwaZulu-Natal, extinct in the wild since 1916. Only one male plant was ever found in 1895; all cultivated specimens are male clones, and no female exists.