Botanical Nomenclature

Before the work of Carolus Linnaeus (1707-1778), the botanist who established the binomial system of plant nomenclature, a plant sometimes had a name that consisted of many descriptive words. Linnaeus helped to standardize botanical nomenclature by establishing a genus and species name for each plant, followed by its designator. A clinical report involving a plant must always include the plant's botanical (binomial) name, which consists of both the genus and the species, for example, Duranta repens. By convention, both are italicized or underlined. Duranta is the name of the genus and the first letter is always capitalized. A genus (the plural of which is genera) may be composed of a single species or several hundred. The second part of the binomial, in this case repens, is the particular species within the genus, and it is always in lowercase letters. It is important to include the name of the person (often abbreviated) who named the particular species, as part of the scientific name, to minimize confusion between similar or related plant species. For example, in the case above, the complete name, which would allow the most precise identification, is Duranta repens L.; L. is the accepted abbreviation for Carolus Linnaeus.

Over time, as botanists continue to revise the classification systems of their specific plant families or groups to reflect additional knowledge and a more natural, evolutionarily based system, plants are periodically moved into different genera or sometimes families. A species may be split into several species or varieties, or lumped together with plants of other species to comprise a single species, all based on the expertise of the taxonomist utilizing characteristics from other specialties ranging from gross morphology to molecular biology. One shortcoming of this fluid system is that scientists can have differing opinions as to how to classify a specific plant. To limit confusion with regard to nomenclature, when previously employed names are changed as part of a more recent taxonomic study, they become recognized as synonyms. In this book, the most common current synonyms are included in parentheses with an equal sign, for example, Duranta repens L. (= D.plumferi Jacq.). Some species are divided further into subspecies (ssp.), varieties (var.), cultivated varieties (cultivars (cv.)), and forms (fo.); for example, Philodendron scandens C. Koch & H. Sello ssp. oxycardium (Schott) Bunt. In this instance, the plant was first named Philodendron oxycardium by Heinrich Schott, but was reevaluated and then transferred to become a subspecies of Philodendron scandens by George Bunting. Hybrid names are indicated by an x (multiplication symbol), as in Brugmansia x candida. Horticultural names are not italicized but are capitalized and set in single quotation marks, for example, Ilex glabra cv. 'Compacta.' A printed work can never be fully up to date from a taxonomic standpoint because taxonomists are constantly refining the classification systems of the groups on which they work. At the same time, there may be a significant volume of medical literature based on an "older" name, and thus, for most efficient and rapid use of the information in this volume, some of the older names used in the first edition are retained.

Associations of like genera are placed in a family. The family name is not italicized, but the initial letter is always capitalized. Botanists have changed the status of some families to reflect a more natural evolutionary lineage, either by incorporating them into other families and dropping their original designation or by creating entirely new families. Since the publication of the original edition of this Handbook, family names for some of the genera have been changed, but in this new edition the older name has been maintained to facilitate rapid consultation of the toxicological literature, and the new name is added in parentheses, for example, Umbelliferae (= Apiaceae). We also head many of the poisoning syndromes in Section 2 with the name of the genus followed by the word "species" (spp.) to indicate that there are several to many species in this genus having toxic properties.

If an individual species cannot be found, but the genus is listed, it should be assumed, conservatively, that the species has a potential for toxicity similar to another member of that genus. To a lesser extent, such an association may exist for members of the same family (Table 3). These relationships are far from exact, and inconsistencies in the clinical presentation or therapeutic response of an exposed patient should prompt immediate consultation with a Poison Control Center or other expert source. The botanical nomenclature used in this book has been derived from various sources, as well as the opinions of specialist reviewers.

There are no rules for establishing common names of plants. Common names can be highly misleading and may erroneously suggest toxicity or the lack of toxicity. For example, a plant known as a "pepper" plant could be the sweet pepper commonly eaten as a vegetable (Capsicum annuum L. var. annuum); or one of the extremely hot, virtually "inedible" peppers (particularly when eaten in quantity and certainly depending on the person's palate) used as a decorative houseplant in that same species but containing significant quantities of capsaicin; or the spice plant from which we derive black pepper (Piper nigrum); or the pepper bush (Leucothoe species) containing grayanotoxins; or the pepper tree (Schinus molle) with triterpene-containing berries; or any number of other species with "pepper" as part of its common name. Another

TABLE 3. Examples of Plants Producing Systemic Poisoning in Humans Arranged by Family and Genus

Amaryllidaceae

Berberidaceae

Euphorbiaceae

Amaryllis

Caulophyllum

Aleurites

Hippeastrum

Podophyllum

Euphorbia

Clivia

Hippomane

Crinum

Boraginaceae

Hura

Galanthus

Echium

Jatropha

Hymenocallis

Heliotropium

Manihot

Lycoris

Pedilanthus

Narcissus

Calycanthaceae

Ricinus

Zephyranthes

Calycanthus

Ginkgoaceae

Anacardiaceae

Campanulaceae

Ginkgo

Schinus

Hippobroma

Lobelia

Guttiferae

Apocynaceae

Calophyllum

Acokanthera

Caprifoliaceae

Clusia

Adenium

Lonicera

Allamanda

Sambucus

Hippocastanaceae

Nerium

Symphoricarpos

Aesculus

Pentalinon

Thevetia

Celastraceae

Iridaceae

Celastrus

Iris

Aquifoliaceae

Euonymus

Ilex

Leguminosae

Compositae

Abrus

Araceae

Senecio

Baptisia

Arum

Caesalpinia

Alocasia

Coriariaceae

Cassia

Anthurium

Coriaria

Crotalaria

Arisaema

Gymnocladus

Caladium

Cornaceae

Laburnum

Calla

Aucuba

Leucaena

Colocasia

Pachyrhizus

Dieffenbachia

Corynocarpaceae

Robinia

Epipremnum

Corynocarpus

Sesbania

Raphidophora

Sophora

Monstera

Cucurbitaceae

Wisteria

Philodendron

Momordica

Spathiphyllum

Lilliaceae

Symplocarpus

Cycadaceae

Allium

Xanthosoma

Cycas

Aloe

Zantedeschia

Bulbocodium

Ericaceae

Colchicum

Araliaceae

Kalmia

Convallaria

Hedera

Leucothoe

Gloriosa

Lyonia

Ornithogalum

Asclepiadaceae

Pernettya

Schoenocaulon

Calotropis

Pieris

Scilla

Cryptostegia

Rhododendron

Urginea

Veratrum

Zigadenus

TABLE 3. Continued

Loganiaceae

Ranunculaceae

Solanaceae

Gelsemium

Aconitum

Atropa

Spigelia

Actaea

Capsicum

Strychnos

Adonis

Cestrum

Anemone

Datura

Loranthaceae

Caltha

Brugmansia

Phoradendron

Clematis

Hyoscyamus

Viscum

Helleborus

Lycium

Pulsatilla

Nicotiana

Meliaceae

Ranunculus

Physalis

Melia

Solandra

Swietenia

Rhamnaceae

Solanum

Karwinskia

Menispermaceae

Rhamnus

Taxaceae

Menispermum

Taxus

Rosaceae

Myoporaceae

Eriobotrya

Thymelaeaceae

Myoporum

Malus

Daphne

Prunus

Dirca

Oleaceae

Rhodotypos

Ligustrum

Umbelliferae

Rutaceae

Aethusa

Palmae

Poncirus

Cicuta

Caryota

Conium

Sapindaceae

Oenanthe

Papaveraceae

Blighia

Chelidonium

Sapindus

Verbenaceae

Duranta

Phytolaccaceae

Saxifragaceae

Lantana

Phytolacca

Hydrangea

Rivina

Zamiaceae

Scrophulariaceae

Zamia

Polygonaceae

Digitalis

Rheum

problem associated with common names is that they can sometimes lead to the assumption that plants are related—either botanically or toxicologically. For example the "hellebore," Helleborus niger L., is in the family Ranunculaceae, but it bears no relationship to the "false hellebore," Veratrum viride Aiton, a member of the family Liliaceae; the former species contains toxic glycosides and saponins and the latter contains toxic alkaloids. The botanical (binomial) nomenclature is essential for ensuring proper plant identification.

Common names are included throughout this book only to facilitate in the identification of a particular plant in question. Many common names are no longer in use and others have been developed, but there is no way to verify contemporary use except by interviewing the inhabitants of a region and record ing their responses. Thus, for a compilation of common names in this text we depended on the literature. The common names of native species from the United States and Canada are taken from Kartesz and Kartesz (1980). Names for West Indian species and Guam were selected from the floras listed in the references. Common names for cultivated plants were taken primarily from Hortus Third. In addition to floras, Hawaiian names are from Neal (1965), Cuban names from Roig y Mesa (1953), and Mexican names from Aguilar and Zolla (1982). Many less-common, older names for plants in the United States were selected from Clute (1940). When bolded, the common name connotes the most widely employed name in contemporary use in the United States.

Care must be exercised when evaluating poisonous plant literature. In some instances, information on the toxicity of plants in grazing animals is extrapolated to predict that which may occur in humans. Unsubstantiated plant lore has passed through generations of textbooks; we have attempted to remove as much lore as possible. Even evaluations based on human case reports, which act as the foundation for this book, may be flawed by erroneous identification of the plants or inappropriate attribution of the clinical effects to the plant.

Glossary of Botanical Terms

This list of botanical and horticultural terms is provided to aid in understanding the plant descriptions found in the text. The terms have mostly been taken from two primary references, Manual of Vascular Plants of Northeastern United States and Adjacent Canada, Second Edition (Henry A. Gleason and Arthur Cronquist, 1991) and Hortus Third: A Concise Dictionary of Plants Cultivated in the United States and Canada (Liberty Hyde Bailey and Ethel Zoe Bailey, Revised and Expanded by The Staff of the Liberty Hyde Bailey Hortorium, 1976). Some definitions have been modified from the original for ease of use and understanding by the nonbotanist, and the reader is urged to consult a botanical textbook if greater detail is required. The botanical illustrations are by Bobbi Angell.

Alternate: Arranged singly at different heights and on different sides of the stem— as in alternate leaves.

Annual: Yearly; a plant that germinates, flowers, and sets seed during a single growing season.

Anther: The portion of the stamen of a flower that contains the pollen, usually having two connected pollen sacs.

Aril: A specialized, usually ^ aril fleshy outgrowth that is attached to the mature seed; more loosely, any appendage or thickening of the seed coat.

Bark: Outer surface of the trunk of a tree or woody shrub.

Bearded: Bearing a tuft or ring of rather long hairs.

Berry: The most generalized type of fleshy fruit, derived from a single pistil, fleshy throughout, and containing usually several or many seeds; more loosely, any pulpy or juicy fruit.

Biennial: Living 2 years only and blooming the second year.

Blade: The expanded, terminal portion of a flat organ such as a leaf, petal, or sepal, in contrast to the narrowed basal portion.

Bony: Hard surface as in a bone.

Bract: Any more or less reduced or modified leaf associated with a flower or an inflorescence that is not part of the flower itself.

Bulbil, bulblet: Diminutive of bulb; one of the small new bulbs arising around the parent bulb; a bulblike structure produced by some plants in the axils of leaves or in place of flowers.

Bulb: A short vertical, underground shoot that has modified leaves or thickened leaf bases prominently developed as food-storage organs. ^

bulb

Buttress: Flattened support structures at the base of the trunk of certain types of trees, particularly in the tropics.

Structure Calyx Flower
Calyx: All the sepals of a flower, collectively.

Capsule: A dry, dehiscent fruit composed of more than one carpel.

Carpel: The fertile leaf of an angiosperm that bears the ovules. The pistil (female part of the flower) is made up of one or more carpels, where the seeds normally are found.

Climbing: Growing more or less erect without fully supporting its own weight, instead leaning, scrambling, twining, or attaching onto some other structure such as a tree or wall.

Coarse: Rough, as in the texture of a leaf.

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