''Platanus racemosa'' is a species of

plane tree ''Platanus'' ( ) is a genus consisting of a small number of tree species native to the Northern Hemisphere. They are the sole living members of the family Platanaceae. All mature members of ''Platanus'' are tall, reaching in height. The type ...

known by several common names, including California sycamore, western sycamore, California plane tree, and in North American Spanish . ''Platanus racemosa'' is native to

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

and

Baja California Baja California, officially the Free and Sovereign State of Baja California, is a state in Mexico. It is the northwesternmost of the 32 federal entities of Mexico. Before becoming a state in 1952, the area was known as the North Territory of B ...

, where it grows in

riparian A riparian zone or riparian area is the interface between land and a river or stream. In some regions, the terms riparian woodland, riparian forest, riparian buffer zone, riparian corridor, and riparian strip are used to characterize a ripar ...

areas,

canyon A canyon (; archaic British English spelling: ''cañon''), gorge or chasm, is a deep cleft between escarpments or cliffs resulting from weathering and the erosive activity of a river over geologic time scales. Rivers have a natural tendency t ...

floodplain A floodplain or flood plain or bottomlands is an area of land adjacent to a river. Floodplains stretch from the banks of a river channel to the base of the enclosing valley, and experience flooding during periods of high Discharge (hydrolog ...

s, at springs and seeps, and along

stream A stream is a continuous body of water, body of surface water Current (stream), flowing within the stream bed, bed and bank (geography), banks of a channel (geography), channel. Depending on its location or certain characteristics, a strea ...

s and

river A river is a natural stream of fresh water that flows on land or inside Subterranean river, caves towards another body of water at a lower elevation, such as an ocean, lake, or another river. A river may run dry before reaching the end of ...

s in several types of

habitat In ecology, habitat refers to the array of resources, biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species' habitat can be seen as the physical manifestation of its ...

s.Santa Monica Mountains National Recreation Area (N.R.A.), General Management Plan (GMP): Environmental Impact Statement. United States: n.p., 1982. It can be found as far north as Tehama and Humboldt counties.

Description

This large tree grows to in height with a trunk diameter of up to one meter (three feet). The height of these trees ranges from . A specimen on the campus of

Stanford University Leland Stanford Junior University, commonly referred to as Stanford University, is a Private university, private research university in Stanford, California, United States. It was founded in 1885 by railroad magnate Leland Stanford (the eighth ...

has a trunk girth (circumference) of . The trunk generally divides into two or more large trunks splitting into many branches. The bark is an attractive patchwork of white, tawny beige, pinkish gray, and pale brown. Both older bark and twigs on this plane sycamore become darker with time. The twigs and bark range from a light brownish gray to a shade resembling the color sepia. ''Platanus racemosa'' is the dominant species in the globally and state endangered sycamore-alluvial woodland habitat. Platanus racemosa-3

The large palmately lobed

leaves A leaf (: leaves) is a principal appendage of the stem of a vascular plant, usually borne laterally above ground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, stem, ...

may be up to centimeters wide and have three or five pointed lobes. New leaves are a bright translucent green and somewhat woolly. The

deciduous In the fields of horticulture and botany, the term deciduous () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed Leaf, leaves, usually in the autumn; to the shedding of petals, aft ...

tree drops copious amounts of dry golden to orangish red leaves in the fall. The

inflorescence In botany, an inflorescence is a group or cluster of flowers arranged on a plant's Plant stem, stem that is composed of a main branch or a system of branches. An inflorescence is categorized on the basis of the arrangement of flowers on a mai ...

is made up of a few spherical flower heads each around a centimeter wide. The female flower heads develop into spherical fruit clusters each made up of many hairy, maroon-red-woolly

achene An achene (; ), also sometimes called akene and occasionally achenium or achenocarp, is a type of simple fruit, simple dry fruits, dry fruit produced by many species of flowering plants. Achenes are monocarpellate (formed from one carpel) and Dehi ...

s. Depending on the sex, the

can either be red, if female, or chartreuse, if male. After the female clusters fertilize, the achenes bear a fruit that breaks apart and scatters just as the tree's pollen does. The tough and coarse-grained wood is difficult to split and work. It has various uses, including acting as a meat preparation block for

butchers A butcher is a person who may slaughter animals, dress their flesh, sell their meat, or participate within any combination of these three tasks. They may prepare standard cuts of meat and poultry for sale in retail or wholesale food establishme ...

. Many small birds feed on its fruit, and several mammals eat its twigs and bark. The

pollen Pollen is a powdery substance produced by most types of flowers of seed plants for the purpose of sexual reproduction. It consists of pollen grains (highly reduced Gametophyte#Heterospory, microgametophytes), which produce male gametes (sperm ...

resulting from the hairs on the leaves and flowers of Western sycamores can be

allergen An allergen is an otherwise harmless substance that triggers an allergic reaction in sensitive individuals by stimulating an immune response. In technical terms, an allergen is an antigen that is capable of stimulating a type-I hypersensitivi ...

s for some people. New leaves are susceptible to anthracnose canker, which, when it causes a side bud to become the new leader, can create picturesque angling trunks and branches on older specimens.

Cultivation

It is also widely planted horticulturally as a landscape tree in public landscapes and private gardens. While it requires some water, and can be grown in lawns, once established it is drought tolerant. New appreciation for how it shades sun in summer and lets sun through in winter has led to its use in

green architecture Sustainable architecture is architecture that seeks to minimize the negative environmental impact of buildings through improved efficiency and moderation in the use of materials, energy, development space and the ecosystem at large. Sometimes, s ...

and

sustainable design Environmentally sustainable design (also called environmentally conscious design, eco-design, etc.) is the philosophy of designing physical objects, the built environment, and services to comply with the principles of ecological sustainability ...

Uses

California sycamore wood is extremely hard and difficult to work, but can still be employed to create a variety of items such as

button A button is a fastener that joins two pieces of fabric together by slipping through a loop or by sliding through a buttonhole. In modern clothing and fashion design, buttons are commonly made of plastic but also may be made of metal, wood, or ...

s, tobacco boxes, furniture, wooden utensils, and barrels. The form and wide canopy of the species make it an effective shade tree. This western sycamore's shade cools the surrounding bodies of water while simultaneously offering a home for some animals in the humid environment in which it flourishes.

Ecology

Increased human interference has made the ''P. racemosa'' more susceptible to cross-breeding with other Platanus trees. This hybridization with other species like the ''P. x acerifolia'' offers the ''P. racemosa'' the advantage of resisting

fungal diseases Pathogenic fungi are fungi A fungus (: fungi , , , or ; or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and mold (fungus), molds, as well as the more familiar mushrooms. These orga ...

, namely the sycamore anthracnose. Interbred California sycamores are less vulnerable to this disease than the original ''P. racemosa'' as it harms their wood. However, sycamore anthracnose produces deadwood which creates a habitat for animals like

wood duck The wood duck or Carolina duck (''Aix sponsa'') is a partially migratory species of perching duck found in North America. The male is one of the most colorful North American waterfowls. Taxonomy The wood duck was Species description, formal ...

s. The lack of non-hybridized ''P. racemosa'' thus harms the riparian woodlands in which they thrive. Another disease that the ''P. racemosa'' is particularly receptive to is the ''Fusarium dieback'' which is carried and passed on through two kinds of invasive

ambrosia beetle Ambrosia beetles are beetles of the weevil subfamilies Scolytinae and Platypodinae (Coleoptera, Curculionidae), which live in nutritional symbiosis with ambrosia fungi. The beetles excavate tunnels in dead or stressed trees into which they introduc ...

s. Removing the tree itself is one way to prevent the significant harms of ''Fusarium dieback'' from spreading but a mixture of

fungicide Fungicides are pesticides used to kill parasitic fungi or their spores. Fungi can cause serious damage in agriculture, resulting in losses of yield and quality. Fungicides are used both in agriculture and to fight fungal infections in animals, ...

s such as metconazole combined with an

insecticide Insecticides are pesticides used to kill insects. They include ovicides and larvicides used against insect eggs and larvae, respectively. The major use of insecticides is in agriculture, but they are also used in home and garden settings, i ...

can additionally reduce the number of ambrosia beetles that transmit this disease. Close monitoring is required in order to prevent a substantial beetle

infestation Infestation is the state of being invaded or overrun by pests or parasites. It can also refer to the actual organisms living on or within a host. Terminology In general, the term "infestation" refers to parasitic diseases caused by animals su ...

from occurring as that would damage the tree to the point of needing removal. Further hybridization between the ''P. racemosa'' and ''P. x hispanica'' are a threat to the genetic diversity and identity of the former. The disease combatant advantage that the hybrid provides can bring about a decline in the native tree. The ensuing decline and genetic disintegration could not only harm the tree itself, but nesting birds,

monarch butterflies The monarch butterfly or simply monarch (''Danaus plexippus'') is a milkweed butterfly (subfamily Danainae) in the family Nymphalidae. Other common names, depending on region, include milkweed, common tiger, wanderer, and black-veined brown. ...

, and numerous other small animals that reside or find shelter within the California sycamore's shade. D. Whitlock's study on the

RNA Ribonucleic acid (RNA) is a polymeric molecule that is essential for most biological functions, either by performing the function itself (non-coding RNA) or by forming a template for the production of proteins (messenger RNA). RNA and deoxyrib ...

of the ''Platanus'' trees near the

Sacramento River The Sacramento River () is the principal river of Northern California in the United States and is the largest river in California. Rising in the Klamath Mountains, the river flows south for before reaching the Sacramento–San Joaquin River D ...

reveals that ''P. racemosa'' contains

gene In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei ...

s from ''P. x hispanica,'' which consequently demonstrates the increased erasure of the former. Platanus racemosa-6

References