The vast majority of books about the native plants of Texas are field guides, in one form or another. Given Texas' extraordinary botanical wealth and diversity, with approximately 6000 species spread across more than 268,000 square miles including several distinct floristic regions, this is entirely understandable. There is a simple need to know the names of the plants, how to recognize them, and how to distinguish them from similar species. But once we know what we are looking at—whether a pecan, prickly pear, or bluebonnet—is there nothing more to know? Is there anything remarkable or noteworthy about the plant? Did it play a role in history? Is it useful to humankind? Does it contain medicinal, psychotropic, or toxic compounds? Is there unusual ecological or biological information about it? Is it particularly important to wildlife—birds, bees, or butterflies? Does it have cultural significance today, and if so, why? In short, what is its story?
These are precisely the questions that this book addresses, the stories it attempts to tell. This work is ethnobotanical in the broadest sense. More than simply a listing of the human uses of plants (though a great many are included), this work explores our vast array of connections to them. These connections come from many fields and disciplines, including the natural sciences (biology, chemistry, ecology, pharmacology, taxonomy), social sciences (archaeology, history, linguistics), and humanities (folklore, legends, and traditions). The peoples involved reflect the historic diversity of Texas, including prehistoric peoples, indigenous tribes who lived in or moved through the state, French and Spanish explorers, Hispanic and Anglo settlers, and contemporary citizens. Sources run the gamut from archaeological findings, chronicles, pioneer journals and diaries, reports from early scientific expeditions, ethnobotanical works on Native Americans, studies of African American folk healers, cowboy ballads, state symbols and place names, current scientific articles, and even interviews with contemporary naturalists, ranchers, and other lovers of the land.
Each plant has its own story to tell and leads where it will. Some plants, such as lechuguilla, sotol, and yucca, are especially rich in the Texan archaeological record, providing documented fiber and foodstuffs for millennia. Other plants, such as jimsonweed and peyote, are known for their psychotropic compounds. Horsemint, sassafras, and yaupon make famous teas, and the fruits of agarita, mesquite, persimmon, and prickly pear provide jellies and preserves. But these stories are by no means one-dimensional, or centered on economic botany. Each narrative makes its twists and turns according to the landscape that surrounds it.
For instance, live oak once provided a source of food, tannin, and ink, but it also is one of the heaviest of American woods, supplying one of the strongest shipbuilding woods available in the world. It gave the USS Constitution (Old Ironsides) her military advantage and helped to establish the supremacy of the U.S. merchant marines. Live oak became the first North American tree to be set aside for future use in a forest preserve. A cluster of live oaks on Galveston Island was the greenery that first greeted early Texas immigrants arriving on our shores. Fully half of all the historic trees of Texas are live oaks, commemorating such things as treaties, battles, encampments, trysts, and buried treasure. Live oak leaves, denoting strength, even grace the Official State Seal of Texas.
Such a broad approach reaches beyond mere laundry lists of well-known uses to locate the unusual, the forgotten, the unknown but must-know things about our native flora. Horsetail, for example, is known as the Tinkertoy plant among children, who pull its stems apart and reattach them for sport. Plant enthusiasts may refer to the reedlike herb as scouring-rush on account of its rough, sandpapery surface. How many of us are aware that horsetail is a living fossil, with ancestors dating back more than 350 million years, to when tree-sized horsetails composed some of the earth's first extensive forests? Or take yaupon, an evergreen shrub increasingly used in landscaping throughout the state. Practically every indigenous tribe of the American Southeast drank a naturally caffeinated tea from its leaves, as did many European explorers, colonizers, and settlers. Our knowledge of this native tea has all but vanished, while the tea known as mate, from a close relative of yaupon in South America, has remained a common drink and source of regional identity and pride. How many of us know that bald cypress trees were once so large that dances could be held on their stumps, or that cypress shingle-maker camps developed into some of the first settlements of the Hill Country? Who would guess that the fruits of the weedy silverleaf nightshade, ubiquitous in roadway medians, can curdle milk and were originally used to make asadero cheese, a common ingredient of chile con queso?
In choosing which plants to cover, my approach is to take a bird's-eye view of the entire native vascular flora of Texas (including trees, shrubs, wildflowers, grasses, cacti, vines, and aquatics) and ask which of these are the richest and most interesting in terms of their human (and even wildlife) connections. Which are the ones that appear, again and again, in diaries, journals, reports, and scientific research? Then I balance this group against the plant's abundance and distribution in our state, as it would be of little interest to extol the virtues of a plant that readers would rarely encounter in the wild. Conversely, there is little advantage to including a well-known plant that has a comparatively short or uninteresting story. The selection is naturally a subjective decision that I hope readers will indulge, trusting from their own experience that most of the plants included here are major players in the state's flora. Although some would argue that trees, and to a lesser extent shrubs, have the lion's share of ethnobotanic lore, I purposefully include many herbaceous plants, including wildflowers, for the sake of diversity. Even here, only those with particularly interesting stories make the cut. Wherever possible I focus on the stories that most concern Texas, including broader connections to the Southeast, Southwest, or Mexico when relevant, and reaching yet farther (to the east and west coasts or even to Europe and Asia) only when truly remarkable connections merit it.
This book is written for a broad spectrum of people who are interested in Texas native plants, from novices to experts, from casual observers to plant aficionados, from gardeners and naturalists to landscape architects and botanists, from city dwellers and suburbanites, to ranchers and park rangers. The book does not presuppose botanic knowledge, and technical terminology is kept to a bare minimum. In 65 entries or units, the book covers more than 80 native plant species in 62 genera among 44 families. Although the accounts can essentially stand alone (that is to say, they can be read independently), in an effort to give some order to the lot, I have grouped the plants into three main divisions: trees, shrubs, and everything else. Within each division the plants are listed by genus name, in alphabetical order, but with the common name in bold face and easily visible in the heading. The origin of the scientific name is provided in the heading, and comments on the common names usually appear in the text. The name of the family to which the plant belongs also appears in the heading, along with a thumbnail description of the plant and its habitat and distribution (in Texas, in the United States, and outside the country). Color photos of each plant are provided.
In most cases there is ample information to devote an entire account to one particular species. In many cases, however, two or more species are discussed under the same heading. This can occur when there is sufficient difference between two species to merit discussion, but enough similarity that splitting them would cause redundancy (as is the case with loblolly and longleaf pine, blue and sideoats grama, and Spanish and ball moss). In these examples, both species appear separately in the heading and are clearly distinguished in the text. In other cases, such as hackberry and sotol, folk wisdom may treat several distinct species of one genus in a similar manner, or as happens with well-known entities like plum, sumac, wild onion, and cattail, historical records report as one entity plants that scientists classify as several species. In these cases several scientific names are provided for only one common name; here, again, attention is given to the most common species within our state, taking into account both abundance and distribution. Finally, when there are many species that are widespread, difficult to distinguish, or very similar ethnobotanically, as is the case with amaranth, greenbrier, and yucca, the genus becomes the focus and species are mentioned only to make nuanced distinctions.
The many sources involved in the research of this book are found in the bibliography. How to reference these sources throughout the work took some thought. Cluttering the text with parenthetical citations is unappealing to all save the academic researcher, but completely omitting them smacks of fiction and potentially frustrates those who are interested in delving into particulars. The compromise presented here is to list at the end of each account a reference to every work that was consulted in its writing, interrupting the narrative only to cite direct quotations or points that rely heavily on a specific source.
This book will fill a niche that is overlooked in the available literature. The work that is most similar to it, Ellen Schulz's Texas Wild Flowers: A Popular Account of the Common Wild Flowers of Texas, is long out of print (1928). Another collection of kindred spirit, Donald Culross Peattie's A Natural History of Trees of Eastern and Central North America (1948) and A Natural History of Western Trees (1950), is thorough and beautifully written, but it is limited, of course, to trees. The many current Texas field guides are neither meant to provide, nor have the space for, lengthy commentary, though some exception can be found in Paul Cox and Patty Leslie's concise Texas Trees: A Friendly Guide (1988), Zoe Kirkpatrick's beautiful Wildflowers of the Western Plains (1992), and John and Gloria Tveten's informative Wildflowers of Houston and Southeast Texas (1993). Each of these is limited to a type of flora, a region, or both. Elizabeth Silverthorne's Legends and Lore of Texas Wildflowers (1996) centers on flowers and follows a more literary path. Delena Tull's excellent Edible and Useful Plants of Texas and the Southwest: A Practical Guide (1987), to which this book is indebted, focuses mainly on edible plants and dyes; as the title suggests, the book is meant to provide firsthand, how-to information. Finally, Scooter Cheatham's formidable work, The Useful Wild Plants of Texas (1995), will be the last word on native plant uses, when all twelve volumes of the reference work, covering more than 4000 plants, are completed.
This book then is a one-volume, easy reference for Texas' most common and ethnobotanically interesting plants. It is not limited to a region or a specific type of plant. It can be stowed in the backpack and treated like a field guide, since its structure allows quick access and provides descriptions and photos, and since each plant is treated as a separate entry. It can just as easily be enjoyed as a narrative work, providing the reader with an overview of the natural history of our native plants. Whichever way it is read, I hope this book will open your eyes to the remarkable stories that surround our flora, such that you never look at these plants again in the same way.
Juniperus virginiana L.
Juniperus ashei J. Buchholz
Origin of scientific name
Juniperus is the Latin name for the genus since classical times. Virginiana refers to the colony of Virginia, which in turn was named for Elizabeth I, the Virgin Queen. Ashei honors William Willard Ashe (1872-1932), a senior forest inspector for the U.S. Forest Service and a pioneer in forest research and economics. Ashe planted one of the first commercial stands of longleaf pine in North Carolina.
Other common names
For Juniperus virginiana: red juniper, red cedar, Virginia juniper, Carolina cedar, red savin, Baton Rouge, juniper bush, pencilwood, pencil cedar. For J. ashei: mountain cedar, rock cedar, post cedar, Mexican juniper, brake cedar, Texas cedar, enebro, tascate, taxate, cedro
Cupressaceae (Cypress Family)
Evergreen trees or large shrubs. Juniperus virginiana: 20-50' (up to 120') with variable shape, but often with single main trunk and pyramidal in form; young specimens often resemble Christmas trees. Juniperus ashei: 10-15' high (historically to 50'), many-stemmed when young and frequently bearing gray-white splotches, usually maturing to a single trunk.
Habitat and distribution
The most widely distributed conifer of tree size in this region, Juniperus virginiana inhabits the eastern half of the state and is found throughout the entire eastern U.S. (in every state east of the hundredth meridian). Juniperus ashei occurs in Texas almost exclusively on the limestone soils of the Edwards Plateau, where it inhabits hillsides, canyons, and ravines, often forming extensive thickets; smaller populations in the Arbuckle Mountains of Oklahoma, and in the Ozarks of Arkansas and Missouri; northern Mexico.
Eastern red-cedar is common throughout the eastern half of our state, where it avoids the limestone soils of the western half, being one of the least alkali-tolerant of the drought-hardy trees and shrubs. In the nineteenth century early travelers reported dense "sombre forests of cedar" (Taylor 1936) in the La Grange area and bare trunks up to 60 feet high along the San Jacinto River near Galveston Bay. We should keep in mind that current stands of cedar, like all trees in highly disturbed areas, reflect neither their density within pristine forests nor typical measures of mature height and girth. Eastern red-cedar is an aggressive species that quickly invades disturbed sites. It tolerates many soil types but attains its greatest size in deep alluvial soils receiving annual rainfall of 35 inches or greater. It also makes a great windbreak and is often planted on the Great Plains for its ability to withstand drought, heat, and cold. An authority on Texas gardening points out that the tree, "once established, can withstand more abuse than almost any other tree we grow" (Sperry 1991). Reportedly the species has been in cultivation since 1664, and many cultivars are now available through the nursery trade.
One of the dominant woody plants of the Edwards Plateau, Ashe juniper blankets many of the steeper hillsides and canyons of the Texas Hill Country, such that the shrub and the region are almost inseparable in the mind's eye. Groves on the eastern edge of the Edwards Plateau were noted for their growth in the nineteenth century, and the current National Champion Ashe juniper, at 41 feet high with a spread of 49 feet (as of 2007), is found in the same area in New Braunfels. Ashe juniper commonly has a gray-white fungus, possibly a lichen-forming fungus, growing in splotches on its branches (especially on younger specimens of 20-40 years old). This phenomenon has led some to believe the tree's name comes from the ashen color of the fungus instead of the forest researcher, Mr. Ashe.
Careful research has shown that eastern red-cedar does not hybridize with Ashe juniper even when it overlaps in distribution in the central part of the state. Eastern red-cedar will approach Ashe juniper in habit and appearance, especially when growing on thinner and more alkaline soils; conversely, mature individuals of Ashe juniper with unbranched trunks may occasionally resemble eastern red-cedar.
Among the Anglo settlers of Texas, Juniperus wood (a.k.a. cedar) was favored for housing construction in the mid-nineteenth century, even in east Texas towns that were surrounded by pines. Although log buildings were constructed in Texas out of almost every native timber tree, cedar was used preferentially wherever it was available. Many of the early houses of New Braunfels and Fredericksburg and the crude huts, or jacales, of San Antonio were constructed of cedar. The main reason for this preference lies in cedar wood's durability and fragrance. The wood of both species contains a high level of cedrol and related compounds; these aromatic oils naturally inhibit rot and repel insects, such as termites and moths.
Since eastern red-cedars are usually taller and straighter, and since the color combinations of their red heartwood and white sapwood are unique and striking, their wood was favored in the construction of houses, fences, furniture, closets, and hope chests. Given its softness, straight grain, and freedom from defects, the heartwood was preferred for lead pencils through the early part of the twentieth century, later replaced by incense cedar (Calocedrus sp.) of the western United States. Few now recall that Henry David Thoreau, the nature philosopher of Walden Pond, was involved in his family's cedar-pencil business, which collected its eastern red-cedars in the vicinity. Through Thoreau's research and improvements, his family's pencils were recognized as America's best.
Ashe junipers, usually shorter, more branched, and with higher levels of cedrol in their wood, lent themselves to slightly different purposes. Their wood made especially excellent fence posts, railroad ties, telegraph poles, house blocks, and pier materials. Old-growth Ashe junipers, however, can also attain tall heights (50 feet) and are generally single-trunked. So the many houses, barns, and smokehouses built by early settlers along the eastern edge of the Edwards Plateau, where the distributions of the two species of Juniperus approach each other, probably also contain Ashe juniper. Generally, Ashe juniper wood was utilized for ties and fence posts, since contact with the soil would not cause it to deteriorate, in many cases even after a century of use. In the late nineteenth century, central Texas was one of the main exporters of this wood for these purposes throughout the western United States. Ashe juniper wood was also used historically for fuel (not surprising, given its abundance and the great heat generated by its charcoal). Even as late as the early twentieth century, communities such as Austin were largely dependent on this wood for warmth in winter months.
Cedarwood oil, obtained from both species (but especially Ashe juniper), is commercially important as a fragrance. It is used to scent soaps, room sprays, disinfectants, cosmetics, and especially perfumes, where it is a standard additive not only for its smell but also for its ability to prolong other fragrances. The Texas cedarwood oil industry began in Rock Springs in 1929. There are now several extracting factories in the Hill Country, and cedarwood oil is shipped all over the world.
Native Americans have used juniper wood, bark, and foliage for a variety of purposes over the millennia. The wood of a juniper species was identified from a 7000 BCE hearth in Baker Cave (Val Verde County). Interesting finds in the Shumla caves of the same area included limestone and reed pipes with juniper foliage (instead of tobacco) still within the bowls, as well as a pouch (made from prickly pear pads) stuffed with juniper foliage, which still retained its aromatic fragrance centuries later. The Kiowa and many other Plains Indians have used the smoke of various species of juniper for purification and cleansing, usually placing cedar twigs and leaves on coals to produce the smoke. The long bark of Ashe juniper was also incorporated into softer baskets, cradles, or mats, and it is reported that the Lipan Apache mixed the smaller twigs of cedar foliage with grasses to form a bedding material, on which hides were laid.
Many Indians revered the eastern red-cedar as a "tree of life," using its aromatic leaves, which contain camphor, in sweat lodges and in purification rites. In the Kiowa and Comanche peyote rituals, there was even a "cedar man" dedicated to keeping the cedar-twig incense burning. The Kiowa also carved "love flutes" from the red heartwood (Vestal and Schultes 1939). This tribe also employed small trees and branches, together with cottonwood, to form a screen behind which the performers of the sacred sun dance prepared themselves. Both Kiowa and Comanche used the long straight poles of red-cedar for their tepees, since the wood was durable and unlikely to warp. The Wichita used the wood extensively for posts and poles in the construction of their circular grass lodges, which could reach 30 feet in diameter. The tall-statured Karankawa of the coast made long bows (reaching from foot to chin) of the red-cedar, which were beautifully crafted, and kept them well oiled and polished.
The tribes of the Caddoan Federation of east Texas echoed these uses by employing red-cedar as incense (their infirm were "smoked" with cedar) and as a building material. Intriguing, though, were the nuanced ways in which red-cedar was tied into their religious and ceremonial beliefs. The doors of their houses, for instance, faced only east and west and were preferentially constructed of cedar. According to Caddoan lore, if rites for the dead were not properly conducted, the deceased was in danger of rising up and running away, in which case only a fire of cedar and mulberry could prevent the dead person from becoming a monkeylike "lost timber spirit" (Dorsey 1905). Early Europeans also reported that Caddoan tribes started their fires with fire drills of cedar and mulberry.
There are reports that juniper berries (technically they are fleshy cones) were eaten by Native Americans, but it is likely that these were the fruits of western species of Juniperus and only rarely those of the two species under discussion, which are frequently bitter to the point of being unpalatable, if not inedible. That having been said, German immigrants used Ashe juniper berries very sparingly (one or two berries to a pot) to flavor sauerkraut, sauces, and stews, and current suggestions include crushing a few berries on salmon just before grilling. In larger numbers, the berries are claimed to be an excellent diuretic. The Kiowa chewed eastern red-cedar berries for canker sores in the mouth. The fruits of both species are also eagerly devoured by a large variety of native mammals and birds. The berry of the common juniper of Europe (J. communis) is one of the main flavoring ingredients of gin, which is reflected in the somewhat bitter taste of the alcohol.
Ashe juniper always seems to find itself at the center of an ecological debate. At many sites in its distribution, especially on the eastern edge of the Edwards Plateau, one can stand at an overlook and behold nothing but a vast sea of juniper occasionally interrupted by a grassy knoll or a ribbon of oak. The shrubby tree's prevalence has led to heated debates over its natural (usually understood as pre-European) distribution and density.
On one side are those who maintain that much of the Hill Country, especially its valleys and other areas with good topsoil, should be filled with native prairie grasses, which thrive in such soils. They point out that when the Europeans began to keep livestock within restricted, fenced areas, the practice quickly led to overgrazing. Grasses, with their many fibrous roots, thrive in deep topsoil where their ability to absorb moisture promotes rapid and dense growth, against which few trees and shrubs can compete. At the same time, grasses hold the soil in place; overgrazing reduces grasses, causing soil erosion. This in turn allows juniper seedlings (and those of other woody plants) to compete where once they could not. Ashe juniper, capable of flourishing in rocky limestone with little topsoil (some say it can germinate on bare rock) was able to gain a foothold. Contributing to this new situation was the cessation of fire (whether natural or man-made). The absence of fire allowed woody plants to mature more easily to adulthood, since fast-burning prairie fires destroy seedlings and saplings, sparing more mature trees that can withstand them.
This viewpoint, which has strong merits, can be carried to an extreme, leading people to believe that the entire Hill Country should be a rolling grassland, that Ashe juniper should grow only on a few isolated ledges, or even that it is not native to central Texas at all. So, on the other side, there are those who have begun to point to evidence that juniper has thrived here, even in extensive thickets, or brakes, for a very long time. Numerous reports, from the Spanish explorers of the seventeenth and eighteenth centuries to the Anglo settlers of the nineteenth, describe vast, almost impenetrable thickets of juniper throughout this area, even before any extensive cultivation or grazing took place. Many of the largest specimens were felled for buildings, so that what remained by the latter half of the nineteenth century was not necessarily indicative of the size or density of these groves. Furthermore, it is well known that the rare golden-cheeked warbler migrates every spring from its wintering grounds in southern Mexico and Central America to the Texas Hill Country to nest in mature stands of Ashe juniper, whose long fibers of shredded bark, together with spiderweb silk, provide its sole nesting material. It does not seem plausible that the warbler only discovered the Ashe juniper and the Edwards Plateau in the last couple of hundred years. Finally, one might point out that grazing or farming was rarely attempted on the steeper slopes of the Edwards Plateau, and the arboreal vegetation present there is likely to be, more or less, what it has always been.
Clearly the truth lies somewhere between the two positions. Although there is little doubt that farmers and ranchers of the mid-nineteenth century had a strong impact on the local ecology, a good deal of the general flora of the Edwards Plateau was likely to be at least somewhat (if not fairly) similar to what is found now. It is likely that grasses, extending in from the prairies, did dominate the valleys and river plains, but it is also clear that Ashe juniper naturally inhabited the slopes and rocky ledges where there was little topsoil. In many areas of the Hill Country, such topography allowed for very extensive thickets of the little tree, providing shelter to deer, turkey, and anyone wanting to escape detection. (There are numerous accounts of Native Americans fleeing into these thickets of cedar, at which point their pursuers usually gave up.) The myth of the Hill Country as pure rolling grassland, into which cedars only recently invaded, stems from early twentieth-century observers, who did not realize that the cedars were, in part at least, reclaiming land that had been theirs all along (Weniger 1984).
The pollen of Ashe juniper, produced only on the male trees (the females produce the fruit), is notorious for causing allergies (cedar fever) during pollination season in December through mid-February. Reportedly, a single tree can produce several pounds of pollen (Seiler 2005). Its identification with allergies, together with somewhat exaggerated notions about the shrub's thirst for water, has given the tree a bad name in certain circles. One should always keep in mind the good with the bad. Surely an evergreen, drought-hardy tree that provides shelter and nourishment for many wild animals as well as a highly useful resource for humans should not be condemned lightly. The Ashe juniper is one of the quintessential trees of the Texas Hill Country, one of its most prominent and very native inhabitants.
The names cedar and juniper require comment. Frequently one overhears discussion—sometimes heated—about whether the eastern red-cedar is a "real cedar." Some argue that it is not, while others maintain that it is, especially when compared with Ashe juniper of the Hill Country, which allegedly is not a cedar but rather a juniper. The problem here is one of common names. The biblically famous cedars of Lebanon are members of the genus Cedrus, an Old World genus. If this is what is meant by cedar, then neither the Ashe juniper nor the eastern red-cedar qualifies. Following this logic, neither the Pacific red-cedar nor the yellow cedar (both of the Pacific Northwest) is a cedar, since they belong to the genera Thuja and Chamaecyparis, respectively. Indeed, no tree native to North America is then a cedar, since no member of Cedrus is native to this continent. Such confusion is what led botanists to adopt the Linnaean binomial system. Scientifically, both eastern red-cedar and Ashe juniper are members of the same genus, Juniperus, and you can call them informally cedar or juniper or anything you wish. Common names, after all, reflect local oral traditions and hand-me-down metaphors; they are not intended to convey scientific precision.
With that in mind, cedar is clearly sovereign in common parlance. Texas can boast of almost 60 place names (towns, mountains, hills, lakes, hollows, sloughs, springs, etc.) that contain the word. At least 36 streams are known as Cedar Creek, ranging from Angelina County in east Texas to Brewster County in the Trans-Pecos. Yet there is not a single entity named for juniper. Clearly, the word cedar is ubiquitous and is deeply ingrained in our everyday vocabulary. It is likely that as pioneers from the eastern United States settled the state, the only member of Juniperus with which they were familiar was the eastern red-cedar, and so they used the term cedar indiscriminately for any of the several species of the genus. A final point of interest: Louisiana's capital, Baton Rouge (French for "red stick") is named for the eastern red-cedar.
Adams 1987, 1991, 2004; Adams and Turner 1970; Goodrich and Wiley 1834; Banta and Caldwell 1933; Battey 1876; Berlandier 1980; Bracht 1931; Bray 1904; Canonge 1958; Carlson and Jones 1939; Castetter and Opler 1936; Dennis and Dennis 1925; Dorsey 1904, 1905; Foster 1917; Gatschet 1891; Griffith 1954; Guenther 1973; Hall 1952; Hart and Kemp 1974; Heald and Wolf 1910; Hester 1980; Holley 1836; Hollon and Butler 1956; Jordan 1978; Kindscher 1992; La Vere 1998; Lawson 1990; Martin 1933; Mattoon and Webster 1928; Newcomb 1961; Newkumet and Meredith 1988; Nye 1962; Olmsted 1857; Pulich 1976; Roemer 1935; Seiler 2005; Shafer 1986; Simpson 1988; Smithwick 1983; Sperry 1991; Taylor 1936; Tull 1999; Van Auken 1993; Vestal and Schultes 1939; Vines 1984; Weniger 1984; White 1907; Wrede 1997