• Pteridium

• Rheum

Native to both America and Africa, this family is composed of plants with leaves: alternate. entire; flowers: in racemes, bisexual (or unisexual); calyx: 4- to S- parted; petals: absent; stamens: 3 to many; ovary: superior (or partly inferior); fruit: drupelike berries. Phytolacca americana is the only plant of the Phytolaccaceae found in Pennsylvania.

PHENOLOGY: Pokeweed flowers July through September.

DISTRIBUTION: Found in rich, disturbed soils such as barnyards, lowlands. fields, fencerows. and moist woodland.

PLANT CHARACTERISTICS: Phytolacca americana can be identified by sepals: greenish white to pink; flowers: 6 mm wide; racemes: 1-2 dm, pedunculate; infructescence: nodding; stamens: 10; pistils: 10; fruit: 5-15 cells, a 1 cm thick, juicy (inky), shiny, dark-purple berry; plants: glabrous, perennial herbs, to 3 m tall, branched above; leaves: lance-oblong to ovate, 1-3 dm; petioles: 1-5 cm.

POISONOUS PARTS: All parts, but primarily the roots, are considered poisonous. Small quantities (more than 10) of raw berries can result in serious poisoning of adults. Fatalities in young children can result from the consumption of a few raw berries.

SYMPTOMS: The more common symptoms are gastrointestinal cramps, vomiting, diarrhea, and convulsions in severe cases. Perspiration, prostration, weakened respiration and pulse, salivation, and visual disturbance are possible symptoms. Death may result. Humans experience an immediate burning sensation in the mouth upon consumption. Postmortem: gross lesions: mild to severe gastroenteritis; congestion of internal organs; histological lesions: stomach ulcerations with hemorrhage.

POISONOUS PRINCIPLES: The physiologically active principles have been identified. Suspected compounds include saponin, together with lesser amounts of the alkaloid phytolaccin.

CONFUSED TAXA: Few plants are confused with pokeweed. The infructescence may superficially resemble that of chokecherry or wild cherry (see Prunus), but Prunus is an arborescent plant with woody bark, whereas Phytolacca is herbaceous.

SPECIES OF ANIMALS AFFECTED: Any class could be affected; however, the plant stem, leaves. and berries are unpalatable and therefore are not usually ingested. Pigs may become ill from routing and eating the roots. Humans may be affected if they eat the berries, stems, or roots.

TREATMENT:(11a)(b); (26); peripheral plasmacytosis with potential immunosuppressive properties.

OF INTEREST: Cooked, young, tender leaves and stems are eaten by some people as a pot-herb. These young greens are the "poke salad" of Southern fame. They contain low concentrations of phytolacca toxin which is destroyed by proper cooking. Cooked berries are edible and occasionally used in pies, Phytolacca americana contains mitogens, compounds that can be absorbed through skin abrasions, causing blood abnormalities. Sensitive individuals should handle pokeweed with gloves. Root preparations have been used as a folk-medicinal, a practice than can be dangerous.

GENUS: Podophyllum

Podophyllum peltatum L. —May apple; mandrake

PHENOLOGY: Mandrake flowers in mid-spring, often during May.

DISTRIBUTION: Podophyllum is found in open clearings in moist woods and along road banks as a migrant from adjacent wood lots. It is also encountered in wet or damp meadows, open fields, and pastures.

PLANT CHARACTERISTICS: Podophyllum can be recognized by sepals: 6, falling early; petals: 6-9, white, 1-2 cm long; stamens: twice as many as the petals; ovary: oval, with a large sessile stigma; fruit: yellow when ripe, 4-5 cm, fleshy pulp edible, many-seeded; plants: in colonies; perennial from a rhizome; the flowering stem with two, umbrella-shaped leaves and a short-peduncled, solitary flower in the axil.

POISONOUS PARTS: The herbage, rootstock, and seeds are poisonous.

SYMPTOMS: In humans and livestock symptoms vary and generally involve severe gastroenteritis, diarrhea, vomiting, and violent catharsis.

POISONOUS PRINCIPLES: Podophyllin, a resinoid toxin, is a very complex mixture of lignins (including podophylloxin, alpha- and beta- peltatins) and flavonols Sixteen physiologically active, well-characterized compounds have been isolated in podophyllin. Chemical analysis reveals 3-6% resin and 0.2 – 1.0% podophyllotoxin, picropodophyllin, quercetin, and peltatins.

CONFUSED TAXA: May apples are well known elements of our spring flora. No other plant has umbrellalike leaves and white flowers measuring 5 cm in diameter. It is not readily confused with any other plant.

SPECIES OF ANIMALS AFFECTED: Humans, especially adults, have been poisoned from the misuse of medicinal preparations. The fruits, the least toxic part of the plant, have caused poisoning in children. The principal effect is violent diarrhea and vomiting. Where rhizomes are dried and processed at commercial operations, the handlers often show severe conjunctivitis, keratitis, and ulcerative lesions. As little as 5 grains of podophyllotoxin resin can cause death in humans. A cow is known to have been poisoned in Ontario. The animal displayed diarrhea, salivation, anorexia, lacrimation, and excitement; regions of the face and mouth were swollen and the mucosa congested. Other livestock reported poisoned from May apple or mandrake are hogs and sheep.

TREATMENT: (11a)(b); (26); (1); (3)

OF INTEREST: Preparations from mandake root are commercially available in health food stores. This plant has enjoyed a favored place in homeopathic medicine. Extracts have been used to treat condyloma acuminatum, a type of venereal wart. Prescription preparations still contain podophyllin. Podophyllotoxin is a mitotic poison that kills embryos selectively and is (questionably) teratogenic for surviving fetuses. For this reason pregnant women should avoid the extract of the rootstock. As a mitotic poison, podophyllin and related compounds show tumor-damaging activity and offer some promise in cancer research. Podophyllum resin is extremely caustic to the skin and mucous membranes; the resin dust inflames the eyes. It also has been used internally as a purgative in veterinary science.

GENUS: Prunus

Prunus serotina Ehrh.—Wild black cherry

Prunus virginiana L.—Choke cherry

FAMILY: Rosaceae - the Rose Family

This large family of plants contains many genera and numerous species with leaves: mostly alternate, flowers: bisexual, regular. and 5-merous; stamens: 5 to many, borne on the edge of a calyx tube; pistils: 1 to many; ovary: superior or inferior; fruits: achenes, follicles, berries, pomes, or drupes.

PHENOLOGY: Both species flower in May.

DISTRIBUTION: Both species are found along roadsides, fencerows, waste land, and forest margins.

PLANT CHARACTERISTICS: The two species are similar in appearance. Prunus serotina is a tree to 25 m; leaves: lanceolate to oblong or oblanceolate (ovate in P. virginiana) and 6-12 cm; acuminate at the tip; serrated with incurving, blunt, callous teeth (sharply serrulate in P. virginiana); racemes: 8-15 cm long, terminating current-season leafy twigs; pedicels: 3-6 mm; sepals: 1-1.5 mm long, persistent in P. serotina, deciduous in P. virginiana, flower petals: white and 4 mm long; fruit: dark purple or black (red in P. virginiana); 1 cm thick. The inner bark is aromatic only in P. serotina.

POISONOUS PARTS: Leaves, twigs, bark, and the stone (pit) produce toxicosis.

SYMPTOMS: Poisoning produces anxiety, staggering, falling down, convulsions, dyspnea, rolling of eyes, tongue hanging out of mouth, loss of sensation dilated pupils; the animal then becomes quiet, bloats, and dies within a few hours of ingestion. Postmortem: gross and histological lesions: bright red blood; congestion of internal organs.

POISONOUS PRINCIPLES: Cyanogenic glycosides (prunasin, produced in leaves and twigs, and amygdalin, produced in the pit) release hydrocyanic acid (HCN). Less than 1/4 lb of fresh leaves can be toxic to a 100 lb animal. Conflicting reports suggest wilting may increase HCN release. Wilted leaves are more toxic per unit weight due to loss of water by the leaves, which concentrates the cyanide.

CONFUSED TAXA: The genus Prunus is readily recognized from the description provided. Pokeweed (Phytolacca americana) berries may be confused with those of Prunus (see Phytolacca).

SPECIES OF ANIMAL AFFECTED: Humans and all species of livestock are susceptible to HCN poisoning from the cyanogenic glycosides.

TREATMENT: (11a)(b); (25); (26); immediate injections of sodium thiosulfate and sodium nitrite may alter the minimum lethal dose.

OF INTEREST: Prunus contains many useful plants that also may be poisonous. Peach pits (Prunus persica Batsch.) are rich in cyanide and have been responsible for animal toxicosis. Apricot kernels (Prunus armeniaca L.) have been fatal when consumed by children. Plum pits and bitter almond pits are also cyanogenic. It should be noted that seeds of both the common apple and crabapple (Malus spp ) contain HCN. The death of a man, resulting from eating a cup of apple seeds at once, has been reported.

The poisonous ornamental jetbead bush (Rhodotypos scandens (Thunb.) Mak. = R. tetrapetala Mak.) of horticulture produces a cluster of four, black, shining, berrylike drupes, that are persistent even in winter. The attractive drupes are subtended by 4 spreading, jagged sepals. The shrub grows to 2 m in cultivation. Jetbead has greenish-brown twigs and opposite leaves, glabrous, doubly serrate, to 4 cm long. Symptoms are those for amygdalin poisoning discussed above; treatment; (11a)(b);(25).

GENUS: Pteridium

Pteridium aquilinum (L ) Kuhn—Bracken fern; brake fern

This large family of ferns is delimited by the technical characters of the spore-bearing structures found either on the underside of fronds, or as separate, modified leaves.

PHENOLOGY: Pteridium produces spores in the summer.

DISTRIBUTION: Found in woods, thickets, clearings, and burned areas.

PLANT CHARACTERISTICS: Bracken grows 5-15 dm tall; stem: long, stout erect, with a more spreading blade; blade: ternate and 2-3 times pinnately compound; pinnae: opposite or nearly so; spores: tetrahedral; rhizome: blackish, widely creeping with septate hairs, not scaly; fronds: leathery and deciduous.

POISONOUS PARTS: The entire plant is poisonous in a fresh or dried condition; dead fronds apparently are not harmful.

SYMPTOMS: Horses (and monogastric animals) show anorexia, bradycardia, and incoordination. The animal may crouch with feet apart and back and neck arched. With severe signs there is tachycardia; death occurs with clonic spasms. In ruminants (sheep and cattle) one can see a rough coat, listless attitude, and mucous nasal and oral discharges (possibly bloody) about one week before the serious symptoms occur. In acute cases, an elevated temperature appears. Also there is anorexia and blood in excreta. In a prolonged illness, emaciation, hematuria, and rarely icterus can be observed. In young cattle, there is edematous swelling in the neck region with difficult breathing and death.

Postmortem: gross lesions: in monogastric animals: no significant gross lesions; enteritis with pericardial and epicardial hemorrhages; in ruminants: widespread petechiae and ecchymoses on serosal surfaces, mucosa, heart. muscles, and subautaneous tissue. Abomasal ecchymoses may lead to ulceration; anemia and aplastic bone marrow are present; histological lesions: in monogastric animals: similar to those recorded for Equisetum poisoning; in ruminants: bladder lesions, ureters, or renal pelvis representing chronic severe hyperplasia and hemorrhagic inflammation that may lead to neoplasia. The transitional epithelium has a localized proliferation with metaplasia to mucinous columnar or stratified squamous types, or a combination of both. Hyperplastic epithelium develops neoplastic properties, transforming into a squamous cell or adeno carcinoma that is locally invasive and may spread to regional lymph nodes and lung. Hemorrhage in the urine may be a result of capillaries in the inflammatory lesion becoming hyperplastic and forming hemangiomas in the stroma or on the mucosal surface.

POISONOUS PRINCIPLES: The enzyme thiaminase is suspected in horses. In ruminants the agent of toxicosis is not known but causes hypoplasia or aplasia of hematopoietic tissue.

CONFUSED TAXA: This is the only fern that produces tall, large, coarse fronds from forking, extensively creeping rhizomes.

TREATMENT: Monogastric animals require thiamine treatment. Ruminants are treated with batyl alcohol, antibiotic, antibeparin, and antihistamine.

SPECIES OF ANIMAL AFFECTED: Horses, cattle, sheep, and possibly swine are susceptible.

OF INTEREST: It may take one to three months after ingestion for signs or symptoms to be manifest in thiamine-deficient animals. Six pounds per day for one month will poison a horse. Cattle fed hay with 50% bracken for 30-80 days will be poisoned; more is needed to poison sheep.

Other ferns known or suspected to be poisonous include sensitive fern (Onoclea sensibilis L ). which may produce nervous disorders (horses) and the male fern (Dryopteris felixmas (L.) Schott ), which is suspected to contain thiaminase.

GENUS: Quercus

This economically important family contains the oaks, beeches, chestnut, and numerous other genera of trees. Characteristic features include leaves: alternate, simple, often toothed or cleft (lobed); male flowers: solitary or clustered.

PHENOLOGY: The oaks generally flower in mid-spring, the flowers appearing before the leaves.

DISTRIBUTION: Oaks are familiar trees found in a diversity of habitats from swamps to dry upland woods.

PLANT CHARACTERISTICS: Oak trees are very common and probably recognized by most readers; leaves: pinnately nerved; fruit: an acorn.

POISONOUS PARTS: Acorns and young shoots can cause severe poisoning, especially if eaten in quantity.

SYMPTOMS: Livestock display the following symptoms: anorexia, initial constipation (hard, dark fecal pellets) passing into diarrhea if the animal lives, gastroenteritis, thirst, and excessive urination.

Postmortem: gross lesions: lower half of digestive tract displays mucoid enteritis. becoming hemorrhagic; edema of mesenteric lymph nodes; subcutaneous edema and increased peritoneal and plural fluids; congested liver; gallbladder distended with viscid, brown bile; kidneys are enlarged, pale, uniformly covered with petechiae; histological lesions: brown-stained albumin in proximal convoluted tubules; necrotic epithelial lining cells mixed with proteinaceous substance such that the contents of the lumen form a dense homogeneous mass that is limited by the basement membrane and interstitial tissue.

POISONOUS PRINCIPLES: The toxins are unknown. Oaks contain large amounts of tannin (gallotannins), which has been implicated in poisonings. These substances are broken down into gallic acid and pyrogallol.

CONFUSED TAXA: Oaks are very common and not readily confused with other trees. One major forest type in Pennsylvania is the oak/hickory association. They are also planted for ornamental value.

SPECIES OF ANIMALS AFFECTED: Oaks are more a major problem on western rangeland than in Pennsylvania. Cattle, sheep, horses, and swine have been known to be poisoned. Human poisonings have not been reported.

TREATMENT: (11a)(b); (26)

OF INTEREST: Acorns and, to some extent buds, constitute a major source of wildlife food. Amerindians used acorns in their diet. White oak acorns were usually roasted and ground into a meal for use in "cakes." Books on edible wild plants often suggest eating acorns. Acorns from the white oak group apparently are palatable when cooked. The black oak/red oak group produces very bitter kernels. The white oak group can be differentiated from the red oaks by the presence of a scaly trunk. The tips and lobes of the leaves lacking bristly elongations, and the inside of the acorn smooth. Beech trees also are to be held suspect Beech nuts, the fruit of Fagus grandifolia Ehrh., are reported edible in America; European authors, however, claim they have poisonous properties. They should be avoided, at least in quantity.

GENUS: Ranunculus

Ranunculus abortivus L —abortive buttercup; small-flowered crowfoot

Ranunculus scleretus L.—cursed buttercup

Ranunculus septentrionalis Poir.—Northern buttercup

PHENOLOGY: The abortive buttercup flowers April and May, the cursed buttercup May through August, and the northern buttercup April through June.

DISTRIBUTION: The buttercups are common in Pennsylvania. The abortive buttercup inhabits moist or dry woods; the cursed buttercup, marshes, ditchbanks, and swampy meadows; and the northern buttercup, wet woods and meadows.

PLANT CHARACTERISTICS: Ranuncujus abortivus has petals: yellow, 2-3 mm long, equal to or smaller than the sepals: achenes: with a very short beak, in a short, ovoid head on a villous receptacle. R. scleratus has petals: yellow, 2-3 mm, shorter than the sepals; achenes: nearly beakless, numerous in a short, cylindric head. R.. septentrionalis has petals: yellow, 7-l5 mm, about 2x longer than the sepals; achenes: with a straight beak, 1.8-3 mm long.

POISONOUS PARTS: Fresh leaves and the inflorescence are toxic. Dried material in hay reportedly is not poisonous. Toxicosis varies with amount ingested, stage of plant growth (most toxic at time of flowering), speed and degree of digestion or release of the toxin, growing conditions of the buttercup, and general health or susceptibility of the animal.

SYMPTOMS: Severe gastrointestinal irritation indicated by salivation, decreased appetite, colic, diarrhea. and slow pulse result from poisoning. Milk from affected cows may be bitter and/or reddish. Convulsions, sinking of eyes in their sockets, hematuria, and blindness are seen in severe cases. Horses, goats, and pigs show irritated tissues of the oral cavity. Convulsions may end in death. Buttercup toxicosis displays pulmonary congestion and ecchymotic hemorrhages on the pleural surfaces on postmortem examination.

POISONOUS PRINCIPLES: Toxicity is due to the unstable irritant oil protoanemonin. This oil is volatile and yellow due to lactone. R.. scleratus contains the highest concentration of the oil.

SPECIES OF ANIMAL AFFECTED: All classes of livestock are susceptible.

CONFUSED TAXA: Numerous unrelated plants have 5 bright, yellow petals, although only Ranunculus petals are shiny and porcelainlike. Some members of the Rosaceae have flowers that might superficially resemble those of buttercups. However, the leaves of the rose family bear stipules, which are absent in Ranunculus.

TREATMENT: (11)(b); (26); (5- at a rate of 2 mg subcutaneously. repeated as necessary); (27); (6)

OF INTEREST: Literature records a case of two heifers that were successfully treated for cursed buttercup poisoning. Upon returning to pasture, they selectively ate the R.. scleratus despite ample presence of better forage. These cows apparently developed a desire for this plant after having eaten it as a part of their diet. However, buttercups usually are strongly distasteful to grazing animals and are eaten as a last resort after depletion of more desirable forage.

GENUS: Rheum

Rheum rhaponticum L.—Rhubarb

This family of plants contains at least 40 genera and more than 800 species, all with jointed stems. Other characters include leaf stipules: united into a tubular sheath called an ocrea; sepals: petaloid; petals: absent; fruit: an achene. The Polygonaceae are not known for their poisonous members but for useful ones such as buckwheat and various ornamental plants. Many elements in the family are weedy.

PHENOLOGY: Rhubarb flowers are borne on tall, hollow stalks in the summer.

DISTRIBUTION: Rheum rhaponticum is a cultivated plant that occasionally escapes from the garden.

PLANT CHARACTERISTICS: Rhubarb can be identified by leaves: large, basal, in clumps; ovate with cordate bases; leaf blades: up to 1.5 m long, margins wavy; petioles: as long as leaf blades, often red, stout; sepals: 6, greenish, whitish, or reddish; stamens: 6 (9); fruit: a 3-winged achene.

POISONOUS PARTS: The flat leaf blade is toxic.

SYMPTOMS: Human consumption of the rhubarb leaf results in gastroenteritis, cramps. nausea, vomiting, weakness, respiratory difficulties, irritation of the mouth and throat, poor clotting of the blood, internal hemorrhaging, coma, and death. In hogs the symptoms are staggering, salivation, convulsions, and death.

POISONOUS PRINCIPLES: Oxalic acid, uncharacterized soluble oxalates, and possibly other toxins are believed responsible for poisonings.

CONFUSED TAXA: Burdocks (see Arctium) are often confused with rhubarb. Burdock leaves are coarse and pubescent; the leaves of rhubarb are glabrous.

SPECIES OF ANIMALS AFFECTED: Rhubarb leaves are known to have caused the death of both humans and livestock.

TREATMENT: (11a)(b) with lime water, chalk, or calcium salts; (7); (26)

OF INTEREST: Several species of Rheum are grown for their bold foliage effects in landscaping. No data are available on the toxicity of these ornamental plants.

GENUS: Rhododendron

Rhododendron spp.—Azalea, Rhododendron

POISONOUS PARTS: The foliage of some species is toxic. All taxa are considered potentially poisonous.

POISONOUS PRINCIPLES: The complex mixture andromedotoxin is suspected, as well as the hydroquinone glucoside arbutin.

CONFUSED TAXA: Rhododendrons and azaleas are familiar plants in Pennsylvania. No confusion is readily possible, with the exception of Kalmia(see Kalmia).

TREATMENT: (11a)(b); ( 1); (5); (12)

Many readers will be surprised to learn that the edible cashew nut belongs to the same family of plants as poison ivy and poison sumac. This predominantly tropical family has leaves: alternate, compound; flowers: 5-merous, polypetalous, regular, with an annular disc between the 5 stamens and ovary; ovary: 1-celled, containing I ovule; fruit: a drupe.

PHENOLOGY: Poison ivy produces inconspicuous greenish flowers from May through July.

DISTRIBUTION: Rhus radicans is commonly found in disturbed habitats, food plains, cultivated fields, cemeteries, waste places, along woodland paths, margins of woodlots, fencerows, roadbanks, along streams, and in urban situations around buildings and yards.

PLANT CHARACTERISTICS: The species has complex and variable forms. Some are woody vines that produce aerial roots and grow by straggling and climbing over other vegetation. Ground-forms usually spread by rhizomes and develop dense colonies with a few leaves crowded near the summit. Regardless of growth habit, poison ivy always has three leaflets per leaf, with leaflets: ovate to subrotund, varying to rhombic or elliptic, terminally acute to acuminate, basally cuneate; entire to irregularly serrate or crenate; glabrous or thinly pubescent, petiolule of the terminal leaflet longer than those of the lateral leaflets; panicles: axillary, 1 dm long, bearing greenish-yellow flowers that mature into grayish white fruits, 5-6 mm; fruits: mature August through November, conspicuous all winter; birds eat the ripe seeds with impunity.

POISONOUS PARTS: All parts of poison ivy, with the possible exception of the pollen, contain toxins that cause dermatitis. It has been suggested that extremely sensitive persons might contract poison from wind-blown pollen in spring when the plant is flowering.

SYMPTOMS: Dermatitis ranging from minor reddened and itching skin to major swelling, blisters, and weeping wounds can result from contact. Ingestion of leaves can cause irritation of the mucosa and digestive tract; gastritis and death may result. Animals probably are not as susceptible as humans to contact dermatitis due to hair and fur. Ingestion of leaves or other plant parts by livestock could be dangerous and result in death.

POISONOUS PRINCIPLES: The toxin 3-n-pentadecylcatechol has been isolated from Rhusradicans.

CONFUSED TAXA: The plant most commonly confused with poison ivy is Virginia creeper, Parthenocissus quinquefolia, which produces berries that are poisonous upon ingestion (see Parthenocussus). A reliable feature useful in differentiating the two plants is the compound leaf Virginia creeper has 5 leaflets, whereas poison ivy has 3 leaflets per leaf. Ash tree species in the genus Fraxinus, and boxelder (Acer Negundo L ). can superficially resemble poison ivy, especially as seedlings; however, the former two have opposite leaves, whereas poison ivy has alternate leaves.

SPECIES OF ANIMALS AFFECTED: Contact dermatitis is commonly seen in humans. Fifty percent of the population is allergic in some degree to poison ivy. Consumption of this plant will affect humans, and probably livestock as well.

TREATMENT: For dermatitis: (4); (23); in severe cases steroid injections can reduce the reaction.

OF INTEREST: The following concerning poison ivy are true. They are listed to dispel popular myths.