Parasitic Flowering Plants

Wayne's Word Index Noteworthy Plants Trivia Lemnaceae Biology 101 Botany Scenic Wildflowers Trains Spiders & Insects Search
Noteworthy Plants For November 1999

Parasitic Flowering Plants

Flowering Plants That Live On Other Plants

  Under Construction: More Information And Photos To Come  

When one organism steals all of its food from another organism's body it is called a parasite. The organism who is being robbed of its food supply is called the host. The parasitic mode of existence can be found throughout the kingdoms of life, from bacteria and fungi to insects, arachnids and worms. Parasitism has also evolved in many families of flowering plants. Some heterotrophic flowering plants get their nutrition from mycorrhizal soil fungi that are in turn attached to the roots of forest trees. These interesting plants are called mycotrophic wildflowers or mycoheterotrophs and are discussed in another article called fungus flowers. True plant parasites can be hemiparasitic (semiparasitic) with photosynthetic leaves (such as mistletoe), or holoparasitic and completely dependent on their host (such as dodder). Some stem parasites, such as a local southern California desert native (Pilostyles thurberi), are endoparasitic and live completely within the stems of their host. The only part of Pilostyles that emerges from the host is a tiny bud that opens into a minute red flower. This is similar to a pimple appearing on your face that bursts into a tiny blossom. Of all the more than 230,000 species of flowering plants, the root and stem parasites certainly include some of the most bizarre and beautiful species; including the world's largest flower (Rafflesia arnoldii) that is three feet (one meter) in diameter.

Mistletoes have been collected by people for various reasons. The legendary importance of European mistletoe as a symbol of strength and good fortune, as a powerful and magical cure-all medicine, and in certain paganish rituals may be traced back many centuries; however, the kissing tradition at Christmas appears to be relatively recent in origin and has gained tremendous popularity in North America. Each year children collect sprigs of mistletoe held together by colorful ribbons and sell them during the holiday season.

Stem Parasites

Three common parasitic genera of stem parasites in California include the mistletoes Phoradendron and Arceuthobium of the mistletoe family (Viscaceae), and dodder (Cuscuta) of the morning-glory family (Convolvulaceae). The European mistletoe (Viscum album) has also been found in northern California on maples (Acer), alders (Alnus), elms (Ulmus), willow (Salix), and other deciduous trees. Probably the most widespread mistletoe in California is Phoradendron, a name derived from two Greek words meaning "tree thief." Some species, such as oak mistletoe (P. villosum), have oval, green leaves (the decorative kind used at Christmas), while other species, such as desert mistletoe (P. californicum) have inconspicuous scale-like leaves. The genus Arceuthobium also has small scale-like leaves and commonly grows on cone-bearing trees. It is often called dwarf mistletoe or pine mistletoe.

Different species of mistletoe typically grow on different species of host trees and shrubs. For example, desert mistletoe (Phoradendron californicum) commonly grows on cat-claw acacia (Acacia greggii), although it may also grow on other desert shrubs. Desert mistletoe produces juicy, bright red berries that provide numerous birds with food and water during the winter months. If you walk along a desert wash in the Colorado Desert region of the southwestern United States, you can often spot a black bird called the phainopepla (Phainopepla nitens) near clumps of mistletoe. This bird is easy to identify because of the conspicuous crest on its head. Mistletoe seeds are covered with a musilaginous, glue-like substance called viscin that sticks to the bills of birds. In fact, it resembles rubber cement when the seeds are rolled between your fingers. When birds try to clean their bills, the seeds adhere to the limbs of other trees and shrubs. The seeds also pass through the bird's digestive tract and are transported from one bush to another in the bird's droppings. In fact, this probably explains the derivation of the word mistletoe: from two Germanic words: mista (dung) and tan (twig); referring to bird droppings on a branch or stem. Apparently when the word mistletoe was first used in Europe, people were already aware of the dispersal of mistletoe seeds by birds.

  • Gedalovich, E., Kuijt, J., and N.C. Carpita. 1988. "Chemical Composition of Viscin, An Adhesive Involved in Dispersal of the Parasite Phoradendron californicum (Viscaceae)." Physiological and Molecular Plant Pathology 32 (1): 61-76.

  • Gedalovich-Shedletzky, Delmer, D.P., and J. Kuijt. 1988. "Chemical Composition of Viscin Mucilage from Three Mistletoe Species--A Comparison." Annals of Botany 64 (3): 249-252

    Phoradendron californicum on Cat's Claw Acacia (Acacia greggii)

    Female desert mistletoe (Phoradendron californicum) with flower buds (white arrow) on cat's claw acacia (Acacia greggii). Inset: P. californicum with ripe fruit from a February 2008 image taken in Smoke Tree Wash. The bright berries are a favorite food of the phainopepla.

    Female Phoradendron californicum with flower buds. Perianth segments are valvate in the bud (i.e. margins meet edge-to-edge without overlapping). The flowers are typically 3-merous. Male flowers contain 3 sessile anthers. The entire flower is surrounded by an inflated receptacle that fits neatly into the spike axis. The flower unit slips out of a concave depression in the stem. Female flowers are epigynous with the perianth attached (adnate) to the top of inferior ovary. The perianth segments are interpreted as petals by Hennig S. Heide-Jørgensen in Parasitic Flowering Plants (2008).

    The spike stems are canescent, covered with dense, grayish-white hairs. Another desert mistletoe with scale-like leaves (P. juniperinum syn. P. libocedri) has glabrous stems. The latter species is parasitic on Juniperus and Calocedrus.

    Female Phoradendron californicum with flowers and developing epigynous ovaries.

    Male Phoradendron californicum On Cat's Claw Acacia (Fish Creek)

    One of many spikes on male Phoradendron californicum parasitic on cat's-claw acacia (Acacia greggii).

    Close-Up View Of Female & Male Flowers Slipped Out Of Cavities In Stem

    Phoradendron serotinum ssp. macrophyllum on Western Sycamore

    Dwarf Mistletoe Arceuthobium campylopodium on Pinus jeffreyi)

    Most seeds need to germinate in the soil, but mistletoe seeds can germinate directly on the branches and limbs they are attached to. In most plants the radicle (developing root) grows toward gravity (positive geotropism) and often away from light (negative phototropism). The radicle of a mistletoe seedling can grow directly toward the host, regardless of which side of the host branch it is situated, a rather marvelous adaptation. [This is especially handy if the germinating seed is attached to the underside of a host limb.] The radicle develops into a root-like organ called the haustorium which penetrates the host tissue and begins to absorb water, sugars and amino acids.

    Pine or dwarf mistletoe (Arceuthobium) is especially interesting because sap within the white berries develops considerable hydrostatic pressure causing the berries to literally explode when they are ripe. Placing your warm hands near the ripe berries can hasten the forceful ejection of seeds. Seeds only three millimeters long may shoot up to 49 feet (15 m) laterally, with an initial velocity of about 62 miles (100 km) per hour. The small, sticky seeds can be felt if they strike a sensitive area of your body.

    Dwarf mistletoe (Arceuthobium campylopodum) growing on the branch of a jeffrey pine (Pinus jeffreyi) in the Laguna Mountains of San Diego County, California. The ripe berries are ready to explode and forcibly eject their sticky seeds.

    Galls Caused By Mistletoe

    Some mistletoes cause the host plant to develop galls, masses of woody tissue surrounding the infection. This is especially evident on the stems and branches of oaks where the specialized mistletoe root system (called haustorium) has penetrated the host tissue. Long after the soft-tissued mistletoe has died and withered away, the persistent gall remains on the limbs. Old patriarch oaks may have huge galls several feet in diameter, battle scars from mistletoe attacks many decades before. Mistletoes on cone-bearing trees (such as pines and firs) often cause the terminal branches to become very compact and bushy like a broom. This condition is called a witches' broom.

    Certain tropical mistletoes leave perfect attachment imprints on the host stem long after they have rotted away and fallen off. These club-shaped or mushroom-like malformations of the host wood, intricately sculptured by the impressions of the mistletoe haustorium, are called "wood roses." They are a perfect cast of the parasite's haustorial attachment. In Mexico and Bali, host stems bearing wood roses are carved into all sorts of beautiful figures, including fish, birds and reptiles. These wood roses are not to be confused with the Hawaiian wood rose (Merremia tuberosa), from a yellow-flowered climbing vine in the morning glory family. Known to Polynesian travelers as "wood rose," the enlarged, dried calyx surrounding the seed capsule resembles a lovely rose carved in wood and polished to a satiny-brown finish.

    Parasite wood carvings from Bali and Indonesia. The unusual flared wood rose or gall (red arrow) is an imprint (cast) of the haustorial attachment of a tropical mistletoe. This placenta-like outgrowth is where the host tree supported the large, domelike absorptive organ of the mistletoe. In parasite wood carvings from Indonesia, the host wood is often the chinaberry tree (Melia azedarach) of the mahogany family (Meliaceae), although other woods, such as acacia and mango, are also used. The chinaberry tree is native to Asia and is naturalized in California and throughout the southern U.S.

    The Hawaiian Wood Rose

    Hawaiian wood roses (Merremia tuberosa) are the dried flowers (calyx and seed capsule) of a high-climbing pantropical morning glory. Each capsule contains a cluster of four black seeds.

    Twining Stem Parasites Of The Genus Cuscuta (Convolvulaceae)

    Another common stem parasite in California is dodder or witches' hair (Cuscuta), a member of the fabulous morning-glory family (Convolvulaceae). There are eight native species of dodder in California, often confined to one or relatively few host shrubs. The dodders are sometimes placed in their own family, the Cuscutaceae. Although dodders resemble tangled masses of orange, spaghetti-like strands (or angel-hair pasta) twining over shrubs, they actually produce white flowers that resemble a miniature morning glory blossom. The orange stems of dodder are without chlorophyll and are nonphotosynthetic. Therefore, dodder is an obligate parasite that is completely dependent on its host for water and nutrients. The dodder taps in on its host's nutrient supply with a modified root system (haustorium) that penetrates the stem tissue of the host. It has been estimated that the total length of twining branches produced by a single dodder plant may exceed half a mile (0.8 km). One remarkable species (C. marina) is tolerant of brackish water and parasitizes salt marsh plants, such as Salicornia and Chenopodium, along coastal estuaries.

    A fiery orange mass of dodder (Cuscuta californica) in the chaparral of San Diego County, California. The host shrub, laurel sumac (Malosma laurina) is completely obscured by the dodder.

    Close-up view of the flowers of California dodder (Cuscuta californica) twining around the stem of its host shrub, wild buckwheat (Eriogonum fasciculatum). The flowers are only 3-4 mm in length.

    Dodder (Cuscuta californica) on Sarah. This parasitic member of the morning-glory family (Convolvulaceae) is also known as witches' hair.

    Salt marsh dodder (Cuscuta salina var. salina) in the San Elijo Lagoon, San Diego County. Left: Host plant is Jaumea carnosa (Asteraceae). Right: Host plant is Atriplex triangularis (Chenododiceae).

    A very similar-appearing dodder on many Caribbean islands is Cassytha filiformis of the different and unrelated laurel family (Lauraceae), an extraordinary example of convergent evolution in which a single genus in each family has developed a parasitic mode of life. Like most parasites, mistletoe and dodder can be harmful to the host plant they are growing on. This is especially true if they steal too much moisture and vital nutrients from their host. Dodder can sometimes grow so thick that the host shrub is barely discernible.

    Left: Cassytha filiformis (Lauraceae) on the Caribbean Island of Grand Cayman. Right: Cuscuta californica (Convolvulaceae or Cuscutaceae). These twining, parasitic flowering plants absorb nutrients from their host plants be means of specialized roots called haustoria. This is a good example of convergent evolution in which a single genus in each family has developed a parasitic mode of life.

    Pilostyles: California's Smallest Stem Parasite

    Minute buds and opened flowers of Pilostyles thurberi compared with the head of an ordinary straight pin. When the flowers fall off of the dyeweed stem they leave a circular crater where they were attached. [Scanned 35mm slide from Nikon FM2.]

      Pilostyles: A Seldom-Seen Desert Wildflower  

    Root Parasites

    Without a doubt, some of the strangest and most beautiful flowers on earth come from root parasites. More information and photos about this subject will be uploaded to this site in the near future. Links to WAYNE'S WORD articles about some of these amazing plants are listed in the following table:

    California Ground Cones Boschniakia

    There are several fascinating families of root parasites in the New World region, including the broomrape family (Orobanchaceae), lennoa family (Lennoaceae), sandalwood family (Santalaceae) and the balanophora family (Balanophoraceae). Broomrapes are obligate root parasites that are related to snapdragons (Scrophularia), Indian warrior (Pedicularis) and Indian paintbrush (Castilleja) of the figwort family (Scrophulariaceae). In fact, some members of the figwort family, such as Castilleja and Pedicularis, are partially parasitic on the roots of nearby shrubs. The flower stalk (inflorescence) of some broomrapes resembles a dense snapdragon flower cluster pushing upward through the soil; however, unlike snapdragons, the flower stalk is without photosynthetic leaves and attaches to the roots of its host by a haustorium. The name broomrape is applied to the genus Orobanche and several other related genera. The curious common name is derived from "rapum genistae," referring to a robust, parasitic species that grows on the roots of a leafless shrub called a broom (a species of Cytisus). Perhaps the original people who began using this name thought the parasite resembled an old word vegetable called rape (possibly Brassica napus) . It is doubtful that the common name has anything to do with the verb rape. Some broomrapes, such as the Old Word genus Aeginetia, are quite destructive to crop plants in Asia, including rice, maize (corn) and sugar cane. Broomrapes have some of the smallest seeds in the plant kingdom, small enough to easily pass through the "eye" of an ordinary sewing needle. The seeds can filter down through cracks in the soil and germinate near the roots of their host. One of the most interesting members of this family in the mountains of California is the ground cone (Boschniakia strobilacea), a parasite on the roots of manzanita (Arctostaphylos). The dark, reddish-brown flower stalk is remarkably similar to an upright conifer seed cone, except that flowers protrude from between the scales.

      See Straight Pin & Sewing Needle Used In Wayne's Word Articles   

    California ground cone (Boschniakia strobilacea), a parasitic wildflower that superficially resembles a pine cone, except it has flowers between the scales. Photographed in the San Bernardino Mountains of southern California, attached to the roots of pinemat manzanita (Arctostaphylos patula ssp. platyphylla).

    Broomrapes of the Genus Orobanche

    Orobanche bulbosa, a striking broomrape with a bulbous base that is occasionally found attached to the roots of a chaparral shrub called chamise (Adenostoma fasciculatum). Photographed in the Laguna Mountains of San Diego County, California.

    The flower stalks (inflorescences) of Orobanche parishii ssp. brachyloba (red circle) pushing through the sand at Torrey Pines State Park, San Diego County, California. This broomrape is rarely encountered by botanists.

    Orobanche parishii ssp. brachyloba photographed in May 1982 on Point Loma, San Diego County. This rare species is known only from sandy beaches and bluffs along the coast of central and southern California, Baja California, and the Channel Islands. It commonly parasitizes shrubs of the genus Isocoma (goldenbush), including varieties of I. menziesii.

    The flower stalk (inflorescence) of another broomrape originally identified as Orobanche parishii ssp. parishii emerging from the ground in Valley Center, San Diego County, California.

    The flower stalk (inflorescence) of a broomrape originally identified as Orobanche parishii ssp. parishii. It was emerging from the pine needles along the Laguna Rim Trail in San Diego County, California.

      See Broomrapes On Mt. San Jacinto  

    Orobanche californica ssp. feudgei growing on the roots of sagebrush (Artemisia tridentata) in the San Gabriel Mountains of southern California.

    Orobanche californica ssp. feudgei growing on the roots of sagebrush (Artemisia tridentata) in the San Gabriel Mountains of southern California.

    Orobanche vallicola growing on the roots of coast live oak (Quercus agrifolia) in Claremont, California (Los Angeles County). It is also reported to be parasitic on the roots of elderberry (Sambucus mexicana).

    Orobanche vallicola growing on the root of coast live oak (Quercus agrifolia) in Claremont, California (Los Angeles County).

    Orobanche corymbosa parasitic on the roots of sagebrush (Artemisia tridentata). Photo taken at 7,500 ft. (2286 m) elevation near Lee Vining in Mono County, California.

    Left: Lookout Mountain in the San Gabriel Mountains west of Mt. Baldy. The rare Orobanche vallida grows on a steep talus (scree) slope near the summit.

    Lookout Mountain in the San Gabriel Mountains west of Mt. Baldy. The rare Orobanche vallida grows on a steep talus (scree) slope near the summit. Two flower stalks are shown by red arrows. The broom handle was used as a hiking stick.

    Clustered broom-rape (Orobanche fasciculata) in Kern County, Calif.

    Left. Orobanche uniflora: Tulare Co. (Kings Canyon N.P.). Right. O. fasciculata: Laguna Mtns, San Diego Co.

    Squaw Root (Conopholis mexicana)

    Flower stalks (bearing old flowers and seed capsules) of squaw root (Conopholis mexicana) attached to the roots of Arizona oak (Quercus arizonica) in the Chiricahua Mountains of southeastern Arizona. This unusual wildflower may also be parasitic on the nearby roots of Q. hypoleucoides).

    Flower stalks (bearing old flowers and seed capsules) of squaw root (Conopholis mexicana) in the Chiricahua Mountains of southeastern Arizona.

    The Lennoa Family: The Bizarre Sand Food (Pholisma)

    One of the most interesting of all dune plants, and certainly one of the most bizarre wildflowers in North America is "sand food" (Pholisma sonorae). This amazing parasitic flowering plant grows in the Algodones Dunes of southeastern California and adjacent Arizona, and in the sand dunes of El Gran Desierto in Sonora, Mexico (north of Bahia Adair in the Gulf of California). Within this area, the plants grow on sand dunes produced by wind transport of sand from the beaches of ancient Lake Cahuilla and the Colorado River delta. Another unusual species of sand food (Pholisma culiacana) is endemic to rocky, subtropical thorn scrub 500 miles (800 km) south in Sinaloa, Mexico. The disjunct distribution of these two species may be explained by plate tectonics. Floras west of the San Andreas fault and Gulf rift, in southern California and Baja California, have been displaced northward at least 500 km since the Miocene epoch (about 30 million years ago). Assuming that P. culiacana is more like the tropical progenitor of both species, P. sonorae could have diverged into a more xeric (drought resistant) species west of the San Andreas fault as peninsular California moved northward. Present day populations of P. sonorae east of the fault could have migrated there by shifting sand dunes in the region.

      Wayne's Word Article About Sand Dunes  
    More Images Of Sand Food & San Plant

    Root Parasites Of The Balanophoraceae and Santalaceae

    Two additional families of root parasites in the New World region include the Balanophoraceae and Santalaceae, although both families are well-represented in the Old World. The Balanophoraceae include some truly bizarre root parasites, some of which look more like the fruiting body of a nonvascular soil fungus than a vascular flowering plant. One of the most interesting species is Corynea crassa, a fleshy root parasite that grows in the tropical rain forests of Central America. In Costa Rica this remarkable fly-pollinated species of the wet rain forest is known to parasitize a palm and a bamboo simultaneously (Janzen, 1983).

    Corynaea crassa, a bizarre parasitic flowering plant that truly resembles the fruiting body of a soil fungus. Photographed on Cerro de la Muerte in the Talamanca Range of Costa Rica.

    Corynaea crassa, a bizarre parasitic flowering plant that truly resembles the fruiting body of a soil fungus. Photographed on Cerro de la Muerte in the Talamanca Range of Costa Rica.

    Perhaps the most famous of all parasitic flowering plants are the sandalwoods (Santalum), especially the sandalwood tree of the Old World, S. album. From the dawn of history, sandalwood has been coveted in India and Asia. It is mentioned in the oldest scriptures and the Vedas, which date back many thousands of years. Unlike most popular hardwoods, the heartwood of this tree is sought after for its marvelous, cedar-like scent which is produced by an oil that permeates its xylem tissue. Even after cutting, the wood will exude this pleasant odor for up to 60 years. In fact, sandalwood oil distilled from the wood and seeds is used for cosmetics, medicines, perfumes and lubricants. Ancient civilizations considered sandalwood a valuable commodity, along with gold, silver, amber and ivory. Explorers such as Marco Poco returned to their homelands with fabulous tales of sandalwood, teak, spices and jewels. So great was the demand for this valuable wood, especially for people of great wealth and royalty, that King Solomon himself was a major factor in the extermination of Lebanon's sandalwood forests centuries ago. In fact, there are no untouched sandalwood forest left in the world today. According to Kepler (Hawaiian Heritage Plants, 1984), in the early 1980s, a two by six-inch piece of heartwood sold in India for $20.00 and in New York for about $200.00. Because the tree is a semi-parasitic or facultative root parasite, it is difficult to propagate, and attempts to grow it commercially have resulted in dismal failure. Centuries ago, sandalwood trees were being cut down in India at an astonishing rate, and eventually the sandalwood merchants had to search elsewhere for marketable sources of the wood.

    Haleakala sandalwood (Santalum haleakalae) from the slopes of Haleakala Crater on the Island of Maui. This is one of several species of sandalwood endemic to the Hawaiian Islands. When this species is in full bloom, the flowers typically occur in bright red clusters (panicles) at the ends of the branches.

    The Hawaiian Islands have several native species of sandalwood, including shrubby and tree-like species of lower slopes and scrubby alpine species atop the high volcanic mountains, such as Haleakala Crater. The ancient Hawaiians named it 'la'au-'ala (sweet wood) and 'ili-ahi. They used it to scent their bark cloth (tapa cloth) by pounding chips of its heartwood into the bark of paper mulberry. The fragrance would remain in their clothes for years.

    A sandalwood Ganesha carving and prayer beads from India. The Indian species Santalum album is used for expensive wood carvings; however, because of the rarity of true sandalwood (Santalum), another fragrant wood called red sandalwood (Pterocarpus santalinus) is often used in Indian carvings. The latter species belongs to the legume family (Fabaceae) and is the source of a blood red dye.

    By the time Captain Cook discovered the Hawaiian Islands in 1778, India's supply of sandalwood was rapidly being depleated. This set the stage for Hawaii's entry into the international commercial market. During the 1800s, greedy sandalwood traders made deals with Hawaiian chiefs to cut down the native sandalwood trees, and masted sailing ships carried countless thousands of tons of heartwood to India, Asia and Europe. Soon the native forests of sandalwood and other beautiful hardwoods (such as Acacia koa) were all cut down, a massive deforestation from which these island have never recovered.

    Haleakala sandalwood (Santalum haleakalae) from the slopes of Haleakala Crater on the Island of Maui. This is one of several species of sandalwood endemic to the Hawaiian Islands. When this species is in full bloom, the flowers typically occur in bright red clusters (panicles) at the ends of the branches.

    References About Heterotrophic Flowering Plants

    1. Armstrong, W.P. 1998. "Flowers or Fungi?" Popular Science Annual 1999. Grolier, Inc., Danbury, Connecticut.

    2. Armstrong, W.P. 1997. "Flowering Plants That Mimic Fungi." Zoonooz 70 (10): 20-23.

    3. Armstrong, W.P. 1997. "Carrion Flowers: Not All Flowers Smell as Sweet as a Rose." Zoonooz 70 (1): 24-27.

    4. Armstrong, W.P. 1980. "Sand Food: The Strange Wild Vegetable of the Papagos." Desert Magazine 43 (8): 22-23.

    5. Armstrong, W.P. 1980. "More About Sand Food." Fremontia 8 (2): 30-31.

    6. Armstrong, W.P. 1980. "Sand Food: A Strange Plant of the Algodones Dunes." Fremontia 7 (4): 3-9.

    7. Armstrong, W.P. 1979. "Seldom-Seen Parasitic Wildflowers." Pacific Discovery 32 (6): 10-17.

    8. Armstrong, W.P. 1979. "Pilostyles That Nobody Sees." Environment Southwest No. 484: 17-19.

    9. Armstrong, W.P. 1978. "Parasites of the Desert." (Part II) Desert Magazine 41 (8): 32-35.

    10. Armstrong, W.P. 1978. "Parasites of the Desert." (Part I) Desert Magazine 41 (7): 32-35.

    11. Armstrong, W.P. 1997. "A Tiny Native With An Enormous Relative." Fremontia 5 (3): 20-22.

    12. Heide-Jørgensen, Hennig S. 2008. Parasitic Flowering Plants. Koninklijke Brill NV, Leiden, The Netherlands.

    13. Jansen, D.H. (Editor). 1983. Costa Rican Natural History. The University of Chicago Press, Chicago, Illinois.

    14. Kepler, A.K. 1984. Hawaiian Heritage Plants. Oriental Publishing Company, Honolulu, Hawaii.

    15. Kuijt, Job. 1969. The Biology of Parasitic Flowering Plants. University of California Press, Berkeley, California.

    16. Musselmann, L.J. and W.F. Mann, Jr. 1978. Root Parasites of Southern Forests. U.S. Department of Agriculture, Forest Service, General Technical Report SO-20.

    17. Rock, J.F. 1974. The Indigenous Trees of the Hawaiian Islands. Pacific Tropical Botanical Garden, Lawai, Kauai, Hawaii. Charles E. Tuttle Company, Rutland Vermont.

    18. Walters, D.R. and D.J. Keil. 1996. Vascular Plant Taxonomy. (Fourth Edition). Kendall/Hunt Publishing Co., Dubuque, Iowa.

    Return To WAYNE'S WORD Home Page
    Go To Biology GEE WHIZ TRIVIA Page