Special Topics | School of Biological Sciences | SIU

Although all plants require some water to live, some can tolerate or even require liquid water throughout their lifetime.  Very few embryophytes (land plants) can tolerate saltwater, an exception being the seagrasses (Zostera).  Most aquatics occur in freshwater environments.  These plants can be placed into three general categories based on their overall habit:

• Emergents.  Plants with some portions partially submerged in water, the other parts growing in the air above the water.
• Submergents. Plants with all parts totally submerged. 
• Floating.  Plants floating on the surface of the water, not rooted.

There are many native and non-native aquatic plants that could be listed here, but we will consider only the ones that are commonly seen in cultivation and ones that we actually have in the SIU Greenhouse.

Emergents

• Acorus gramineus.  The native species of  Sweet Flag has been used to make candy from its rhizome.  This species (variegated variety) is purely ornamental.
• Cyperus.  The most commonly seen species is C. alternifolius, the Umbrella Sedge.  This species is similar to C. papyrus, famous for being the source of the writing material papyrus.
• Hydrocotyle.  Although these plants can be grown in a regular pot, many species of Pennywort like to have their feet wet!  The plants grow by means of a rhizome with the peltate leaves occurring at various intervals.  
• Juncus effusus.  This species (and other Juncus as well) have become popular plants for landscaping, especially in outdoor pools.  Some varieties have straight leaves whereas others are contorted (twisted).
• Marsillea.  Water Fern, Four Leaf Clover.  Upon first glance, this plant looks like a Four Leaf Clover (a legume), but is in fact a fern.
• Myriophyllum. The Water Milfoils have highly dissected leaves that occur submerged but the stems can also produce aerial portions whose leaves look very different (heterophylly).  The flowers and fruits are borne on the aerial portions. Species are notoriously difficult to distinguish.
• Sagittaria.  Several species are cultivated, such as S. montevidensis.

Submergents

• Ceratopteris thalictroides.  The Water Sprite is another aquatic fern. This species is a valuable  model research organism because it can be easily grown.
• Elodea.  This popular aquarium plant (also called Anacharis, Egeria, Brazilian Waterweed) has its stems and leaves totally submerged, but the flowering stalk stretches to  the water surface where the flower occurs.
• Isoetes.  The Quilworts are classified as lycophytes, an early branching clade often allied with the ferns.  Many species are emergents in nature but strangely don't object to being grown as submergents.  

Floating

• Azolla.  These floating ferns are sometimes called Water-Velvet.  The fronds are branched, often radiating from a single point.  Interestingly, these fronds often support a symbiotic partner - a cyanobacterium. Because the bacterium can fix atmospheric nitrogen, Azolla plants are often purposely planted on rice paddies in Asia to naturally fertilize the field. However, huge mats of it can compete with other native aquatic plants and animals by blocking the sunlight and reducing oxygen availability.  They also block irrigation pumps, and sometimes cause deaths (by drowning) to livestock that mistake the Azolla mats as soil. See web page HERE for more on control of this plant.
• Eichhornia crassipes.  The Water Hyacinth is an example of too much of a good thing.  Originally from South America, the plant was brought to a flower show in Florida where it escaped a backyard pond.  The rest is history.  The plant now clogs numerous waterways in Florida (and other parts of the world too) where millions or dollars are spend on control.  The plant floats by means of its spongy, air-filled petioles.  A dense mass of roots dangles into the water below the plant. The flowering stalks are aerial producing beautiful blue flowers.  
• Lemna.  Duckweeds are ubiquitous components of any freshwater pond or lake, being dispersed by waterfowl.  The floating "thallus" of the plant is tiny, sometimes with a root protruding downward into the water.  Other aquatic relatives in the family include Spirodela, Wolffia and Wolffiella.
• Pistia stratiotes.  This member of the arum family, called Water Lettuce, is native to Lake Victoria in Africa.  It has been introduced into many freshwater environments worldwide and can become quite invasive.  As with Salvinia, it's leaves are bouyant owing to a dense covering of hairs.
• Salvinia.  The Floating Moss (not a moss!) is actually another fern, like Azolla.  It's fronds are round in shape and covered on the top surface with amazingly tall hairs (trichomes) that branch at the tip.  These effectively trap air making the leaves very bouyant.  

Aquarium Plants

A number of different plants are sold commercially for use in aquaria. Some of these are true aquatics and others are simply plants that can be grown as aquatics, even if they are not usually seen this way in nature. 

• Aponogeton madagascariensis.  Aponogetonaceae. Madagascar Lace Plant
• Anubias barteri.  Araceae. Anubius.
• Anubias congensis (= A. afzelii). Anubius.
• Anubias hastaefolia.   Anubius, Hastate Leaf.
• Anubias nana. Anubius, Dwarf.
• Bacopa monnieri.  Plantaginaceae. Moneywort.
• Cabomba caroliniana. Cabombaceae. Cabomba.
• Ceratophyllum demersum. Ceratophyllaceae. Hornwort.
• Cryptocoryne crispatula. Araceae. Balansae Plant.
• Cryptocoryne spiralis. Spiralis.
• Cryptocoryne wendtii. Cryptocoryne.
• Echinodorus amazonicus. Alismataceae. Amazon Sword Plant.
• Echinodorus cordifolius  Radican Sword, Marble Queen.
• Echinodorus martii. Ruffle Plant.
• Echinodorus osiris.  Melon Sword.
• Echinodorus tenellus. Chainsword Narrow Leaf.
• Eleocharis acicularis.  Cyperaceae. Dwarf Hairgrass.
• Hygrophila angustifolia. Acanthaceae. Temple, Narrow Leaf.
• Hygrophila corymbosa. Temple, Corymbose.
• Hygrophila difformis. Wisteria.
• Lilaeopsis novae-zelandiae.  Apiaceae. Micro Sword.
• Ludwigia glandulosa.  Onagraceae. Ludwigia Peruenis.
• Ludwigia inclinata.  Ludwigia Inclinata.
• Ludwigia repens. Ludwigia, Broad.
• Microsorum pteropus.  Polypodiaceae. Java Fern.
• Myriophyllum heterophyllum. Haloragaceae. Myrio-Red.
• Myriophyllum pinnatum.  Myrio-Green
• Nymphoides aquatica. Menyanthaceae. Banana Plant.
• Rotala indica. Lythraceae. Rotala Indica.
• Rotala macranda. Rotala Magenta.
• Sagittaria platyphylla. Alismataceae. Arrowhead, Flatleaf.
• Sagittaria subulata.  Dwarf Sagittaria.
• Spathiphyllum tasson. Araceae. Brazilian Sword.
• Vallisneria americana. Hydrocharitaceae. Corkscrew Vallisneria.

Cacti (members of the family Cactaceae) and succulents (members of many different families) all have one thing in common: they have modified morphology adapted to conserving water.  Because of these adaptations to dry (xeric) environments, they do not need as much care and attention as other house plants.  On top of that, they have incredibly curious or grotesque shapes and sometimes contrastingly beautiful flowers.  All of these features make them attractive to the collector or enthusiast.  And enthusiasts there are!  These plants are the source for a huge horticultural industry, not only for indoor houseplant use but also for outside landscaping in xeric environments.  There are numerous websites that supply these plants (see Web Pages below) and they are praised and promoted by The Cactus and Succulent Society of America.

The Plant Biology Greenhouse has numerous species of cacti and succulents, as well as some caudiciforms, i.e. plants with swollen, water-storing stems (but not necessarily succulent leaves).  The cactus family is large, with an estimated 118 genera and 1200 species.  Generic boundaries are sometimes not well defined, plus lots of morphological convergence makes identification difficult if the plant is only in vegetative condition (not flowering).  

The list below is arranged taxonomically with links to the genera represented in our collection.

Monocots

Agavaceae

• Agave. 
• Yucca. 

Asphodelaceae

• Aloe. 
• Gasteria. 
• Haworthia. 

Dicots

Aizoaceae

• Delosperma. 
• Faucaria. 
• Fenestraria. 
• Glottiphyllum. 
• Pleiospilos. 
• Rhombophyllum. 

Apocynaceae

• Adenium. 
• Ceropegia. 
• Dischidia. 
• Huernia. 
• Orbea. 
• Stapelia.

Asteraceae

• Kleinia. 
• Senecio. Such as S. jacobsenii. 

Cactaceae

• Astrophytum. 
• Cephalocereus. 
• Cereus. 
• Echinocactus. 
• Echinocereus. 
• Echinopsis. 
• Epiphyllum. 
• Ferocactus. 
• Mammillaria. 
• Opuntia. 
• Pachycereus. 
• Rhipsalis. 
• Schlumbergera. 

Crassulaceae

• Crassula. 
• Echeveria. 
• Graptopetalum. 
• Kalanchoe. 
• Pachyveria. 
• Sedum. 
• Sempervivum. 

Didiereaceae

• Didierea. 
• Portulacaria. 

Euphorbiaceae

• Euphorbia. 
• Monadenium. 
• Pedilanthus. 

Vitaceae

• Cyphostemma. 

Web Pages

• Growing Cacti and Succulents at Home
• Cactus and Succulents Page by Gerard Ardisson. 
• Cactus Art.  
• The Cactus and Succulent Plant Mall. Information on cactus and succulent societies and suppliers of plants, seeds and literature on cacti and succulents. 
• Cacti.com.  Southern California-based web nursery, specializing in landscaping succulents, offering a wide variety of plants including cacti, aloes, agaves, euphorbias, etc. 
• The Cactus and Succulent Society of America.
• Miles' To Go.  Commercial supplier of an amazingly diverse collection of succulents.  

Some of the most unusual and curious plants on the planet are ones that literally "turn the tables" on their animal predators. These plant attract, capture, and absorb nutrients from animals, thus they are called "carnivorous".  It is thought that this trophic (feeding) mode has evolved in response to poor growing conditions, specifically soils lacking in nitrogen.  Evolutionary studies have shown that carnivorous plants evolved at least seven times in separate, independent families: Droseraceae, Drosophyllaceae, Biblidaceae, Nepenthaceae, Cephalotaceae, Sarraceniaceae, and Lentibulariaceae.  There are also some families that contain plants considered "borderline" carnivores, such as Stylidiaceae, Roridulaceae, Martyniaceae, Bromeliaceae and Eriocaulaceae.  An good treatment of carnivorous plants can be found on Wikipedia.

The carnivorous plants can be grouped according to taxonomy or the type of trapping mechanism they use.  The traps include pitfalls, flypaper, snap, bladder, and lobster-pot types.  For the purposes of this web page, the plants will be arranged taxonomically.

Droseraceae

• Aldrovanda.  Relationships to Dionaea and Drosera somewhat unclear. Has a snap-trap mechanism.  Many species known from the fossil record.
• Dionaea muscipula.  Venus Flytrap. One species in this genus from eastern United States. In PLB Greenhouse
• Drosera. Sundews. A genus with over 190 species and a worldwide distribution.  They use a flypaper mechanism of glandular hairs that secrete a sticky mucilage that captures the invertebrates. The leaves undergo movements that also entrap the victim. In PLB Greenhouse

Drosophyllaceae

• Drosophyllum lusitanicum. Portuguese Sundew or Dewy pine. Only one species in this family. Formerly considered part of Droseraceae, molecular evidence indicates it has a separate evolutionary origin.

Biblidaceae

• Byblis.  Rainbow Plants. A genus of about seven species, all from Australia.  It is classified in the order Lamiales and captures invertebrates by means of passive flypaper traps.

Nepenthaceae

• Nepenthes. Tropical Pitcher Plants or Monkey Cups. A genus of ca. 130 species from the Old World tropics.  In PLB Greenhouse

Cephalotaceae

• Cephalotus follicularis. Albany Pitcher Plant.  This family contains only one genus and one species. These Australian plants are classified in Oxalidales. They represent the third independent evolution of pitfall traps (pitchers) in flowering plants.

Sarraceniaceae

• Darlingtonia californica. The Cobra Lily. A genus of one species endemic to northern California and Oregon. 
• Heliamphora.  The Sun or Marsh Pitchers. A genus of 18 species endemic to South America. 
• Sarracenia. The North American Trumpet Pitchers. A genus of 8-11 species of North America.  In PLB Greenhouse.

Lentibulariaceae

• Genlisea.  Corkscrew plant. A genus of ca. 20 species found in Central and South America as well as Africa.  They use underground leaves to attract, trap, and digest their prey, which is mostly protozoans. Although suspected by Darwin, carnivory in this genus was not proven until 1998.
• Pinguicula. Butterworts. A genus of ca. 80 species found in North and South America, Europe and Asia. They capture their prey by a passive flypaper mechanism. In PLB Greenhouse
• Utricularia. Bladderworts.  A genus of over 200 species distributed worldwide.  These plants can be either terrestrial or aquatic and use and incredibly specialized trapping mechanism that involves bladders.  The bladder is under negative pressure (vacuum) and is triggered when the prey stimulates bristle-like protruberances.

Websites

The Carnivorous Plant FAO.  courtesy of The International Carnivorous Plant Society.

Carnivorous Plants & The Fast-Moving Sensitive Plant. From Wayne's Word.

Carnivorous Plants / Insectivorous Plants.  From the Botanical Society of America web site.

Carnivorous Plant Nursery

There are thousands of plants that humans have found economically useful. The list below does not include all uses for our Greenhouse plants. Not included here are plants used purely for ornament (floriculture, horticulture). PLEASE! Do Not Eat any plants in the PLB Greenhouse as all have been treated with pesticides.

Food, Beverage and Condiment Plants

• Agave tequilana (Tequila Plant, Blue Agave).  Fermented leaves source of tequila.
• Ananas comosus (Pineapple).  Fruits eaten.
• Arachis hypogea (Peanut, Groundnut). Seeds eaten.
• Canna edulis (Achira, Edible Canna).  Rhizomes and young shoots eaten.
• Ceratonia siliqua (Carob). Fruits made into chocolate substitute (not that there is such a thing!).
• Cereus peruvianus (Pitaya, Cactus Apple). Fruits eaten.
• Citrus spp. (Citrus, Orange, Lime, Lemon). Fruits eaten.
• Coffea arabica (Coffee). Seeds made into beverage.
• Colocasia esculenta (Taro). Fleshy rhizome and leaves eaten.
• Eriobotrya japonica (Loquat). Fruits eaten.
• Ficus carica (Fig). Fruits eaten.
• Ginkgo biloba (Ginkgo, Maidenhair Tree). Seeds eaten.
• Gnetum gnemon (Melinjo).  Seeds made into flour.
• Ipomoea batatas (Sweet Potato). Fleshy tuberous roots eaten.
• Lablab purpureus (Hyacinth Bean,Lablab Bean). Fruits eaten.
• Malpighia glabra (Acerola, Barbados Cherry).  Fruits eaten.
• Manihot esculenta (Cassava, Tapioca, Yuca). The root is the starchy staple of the tropics, at least after the toxic prussic acid is removed. NOT in Greenhouse (get!).
• Musa spp. (Bananas). Fruits eaten.
• Olea europaea (Olive). Fruits eaten.
• Opuntia ficus-indica (Prickly Pear Cactus). Fruits eaten.
• Phoenix dactylifera (Date Palm).  Fruits eaten.
• Punica granatum (Pomegranate). Fruit eaten.
• Solanum quitoense (Naranjilla).  Fruits eaten.
• Urtica dioica (Stinging Nettle).  Leaves eaten (believe it or not!).

Herbs and Spices

• Antethum graveolens (Dill). Fruits used.
• Capsicum spp. (Chili Peppers). Fruits used.
• Mentha piperita (Peppermint). Leaves used.
• Nepeta cataria (Catnip, Catmint). Leaves used.
• Ocimum basilicum (Basil). Leaves used.
• Piper spp. (Black Pepper).  This species is not the pepper of commerce but a member of the same genus. Black pepper derives from fermented, dried fruits whereas in white pepper the fruits are not fermented.
• Plectranthus amboinicus (Indian Borage).  Leaves used.
• Rosmarinus officinalis (Rosemary). Leaves used.

Perfumes, Flavors, Essential Oils

• Eucalyptus citriodora (Lemon-scented Gum). You have to smell these leaves!
• Vanilla planifolia (Vanilla). Commercial vanilla is derived from the fruits (capsules) that are soaked in alcohol.

Medicinal and Drug Plants

• Ajuga reptans (Bugleweed).  Tannins for treating wounds.
• Atropa acuminata and A. belladona (Belladonna). Produces atropine.
• Catharanthus roseus (Madagascar Periwinkle).  Produces vincristine and vinblastine.
• Digitalis purpurea (Foxglove, Deadmen's Bells, Witch's Bells).  Source of the cardiac glycoside digitoxin.
• Ephedra sp. (Mormon Tea). Source of ephedrine, a decongestant.
• Eschscholzia californica (California Poppy).  Alkaloids used as pain killers.
• Hedera helix (English Ivy).  Various, to treat skin problems.
• Viola tricolor (Pansy).  For treating skin ailments.

Poisonous Plants

• Aglaonema (Aglaonema).  Produces raphides, crystals of calcium oxalate.
• Allamanda cathartica (Common Allamanda, Golden Trumpet).  All parts of the plant but mostly the fruit and sap cause stomach upset.
• Anthurium (Tailflower). Produces raphides, crystals of calcium oxalate.
• Asclepias curasavica (Bloodflower).  Contains cardiac glycosides.
• Caladium (Mother-in-law Plant, Angel-wings). Produces raphides, crystals of calcium oxalate.
• Colocasia (Elephant Ears). Produces raphides, crystals of calcium oxalate
• Datura metel (Metel, Downy Thornapple, Devil's Trumpet).  All members of the genus Datura are poisonous, including the common Jimson Weed (Datura stramonium).   All parts of the plant are poisonous, particularly the seeds.  They contain many alkaloids including hyoscyamine, atropine, and hyoscine (scopolamine).
• Dieffenbachia spp. (Dumb Cane).  Produces raphides, crystals of calcium oxalate as well as some toxic proteins.
• Euphorbia milii (Crown of Thorns).  This species and other members of the family Euphorbiaceae produce milky sap that causes dermatitis and poisoning if ingested.
• Jatropha.  All members of the genus are poisonous, such as J. gossypifolia (Bellyache bush), J. multifida (Physic Nut, Coral Plant), and  J. podagrica(Tartogo, Australian Bottle Plant). Sap from all parts of the plant contains curcin, a toxalbumin.
• Lantana camara (Lantana, Red Sage).  Although commonly cultivated, the fruit (especially the green unripe one) contains the alkaloid lantanin or lantadene.
• Monstera (Windowleaf).  Produces raphides, crystals of calcium oxalate.
• Nerium oleander (Oleander).  Contains cardiac glycosides nerioside and oleandroside.
• Ornithogalum longibracteatum. A relative of this greenhouse plant, O. umbellatum, is poisonous, so this species might be as well.
• Philodendron spp. (Philodendrons).  Produces raphides, crystals of calcium oxalate
• Rhododendron (Azalea, Rhododendron).  Although not often grown in our greenhouse, it is a commonly planted shrub around this and other buildings on campus.  The plants contain andromedotoxin, a toxic resinoid.
• Scindapsus aureus (Golden Pothos).  Produces raphides, crystals of calcium oxalate.
• Zantedeschia spp. (Cala Lily). Produces raphides, crystals of calcium oxalate.

Fiber Plants

• Musa. Members of the genus are not only grown for food but also fiber, such as M. textilis (Abaca, Manila Hemp).
• Agave. All members of the genus produce fibers in their leaves, but A. sisalana (Sisal, Hemp Plant) is cultivated specifically for this purpose.

Dye Plants

Many native plants can be used for dyeing. See the following:

Richards, L. and R. J. Tyrl. 2005.  Dyes from American native plants: a practical guide.  Timber Press. Portland, Oregon.

• Isatis indigotica (Woad). This and other species (e.g. I. tinctoria) are the woad that gives a blue color upon dyeing.

Poisonous Local Plants

The following list of native and commonly cultivated Illinois poisonous plants is included as a general reference. The list contains plants poisonous to livestock as well as people. Those plants listed above are not repeated. This list is not to be considered exhaustive but a work in progress.

Acer spp. including A. rubrum, A. saccharinum. (Maples)
Actaea spp. (Baneberry, Dolls Eyes, White Cohosh, Snakeberry)
Aesculus spp. (Horse Chestnut, Buckeye)
Agrostemma githago (Corn Cockle)
Allium spp. (Onions)
Amaranthus spp. (Pigweed)
Ambrosia spp. (Ragweeds)
Apocynum spp. (Dogbane)
Aquilegia ssp. (Columbine)
Argemone spp. (Prickly Poppy or Mexican Poppy)
Arisaema spp. (Jack in the Pulpit)
Arum italicum (Italian Arum)
Asclepias spp. (Milkweed)
Asparagus officinalis (Asparagus)
Astragalus  spp. (Locoweed)
Brassica spp. (Rape, Cabbage, Turnips, Broccoli, Mustard)
Buxus spp. (Boxwood)
Caltha palustris (Marsh Marigold or Cowslip)
Cannabis sativa (Marijuana)
Centaurea solstitialis (Yellow Star Thistle)
Chelidonium majus (Celandine)
Chenopodium album (Lambs Quarters)
Cicuta spp. (Water Hemlock or Cowbane)
Conium maculatum (Poison Hemlock)
Convallaria majalis (Lily of the Valley)
Cytisus scoparius (Scot Broom)
Delphinium spp. (Delphiniums and Larkspurs)
Dicentra spp. (Bleeding Heart, Squirrel Corn, Dutchmans Breeches)
Digitalis purpurea (Foxglove)
Equisetum spp. (Horsetails)
Eupatorium rugosum (White Snakeroot)
Fagopyrum esculentum (Buckwheat)
Festuca arundinacea (Tall Fescue)
Gelsemium sempervirens (Jessamine)
Glechoma spp. (Ground Ivy, Creeping Charlie, and Gill over the Ground)
Gymnocladus dioicus (Kentucky Coffee Tree)
Helenium amarum [synonym H. tenuifolium] (Bitterweed)
Helleborus spp. (Hellebore, Christmas Rose)
Hyoscyamus niger (Henbane)
Hypericum spp. (St. Johns Wort, Klamath Weed)
Iris spp. (Irises)
Laportea canadensis (Wood Nettle)
Lathyrus spp. (Sweet Pea, Tangier Pea, Everlasting Pea, Caley Pea and Singletary Pea)
Linum usitatissimum (Flax)
Lobelia spp. (Great Lobelia, Cardinal Flower, and Indian Tobacco)
Lotus corniculatus (Birdsfoot Trefoil)
Lupinus spp. (Lupine)
Medicago sativa (Alfalfa or Lucerne)
Menispermum canadense (Moonseed)
Melilotus alba and M. officinalis (White and Yellow Sweetclover)
Narcissus spp. (Daffodil, Jonquil)
Nicotiana spp. (Tobacco and Tree Tobacco)
Onoclea sensibilis (Sensitive Fern)
Papaver spp. (Various Poppies including Opium Poppy)
Parthenocissus quinquefolia (Virginia Creeper)
Phoradendron serotinum (Mistletoe).
Phytolacca americana (Pokeweed)
Pieris spp. (Japanese Pieris, Mountain Fetterbrush)
Pinus ponderosa (Ponderosa Pine)
Podophyllum peltatum (Mayapple and Mandrake)
Prunus spp. (Wild Cherries, Black Cherry, Bitter Cherry, Choke Cherry, Pin Cherry) 
Pteridium aquilinum (Bracken Fern)
Quercus spp. (Oak Trees)
Ranunculus spp. (Buttercups or Crowfoot)
Rheum rhaponticum (Rhubarb)
Ricinus communis (Castor Bean)
Robinia pseudoacacia (Black Locust)
Rumex spp. (Dock)
Sambucus canadensis (Elderberry)
Sanguinaria canadensis (Bloodroot)
Saponaria spp. (Bouncing Bet and Cow Cockle)
Securigera varia (formerly Coronilla varia) (Crown Vetch)
Senecio spp. (Senecio, Groundsels, and Ragworts)
Solanum spp. (Common Nightshade, Black Nightshade, Horse Nettle, Buffalo Bur, Potato)
Sorghum spp. (Sorghum or Milo, Sudan Grass, and Johnson Grass)
Symplocarpus foetidus (Eastern Skunk Cabbage)
Taxus spp. (Yew)
Toxicodendron radicans (Poison ivy) and Toxicodendron toxicarium (Poison oak).
Toxicodendron vernix (Poison Sumac)
Trifolium spp. (Alsike Clover, Red Clover, White Clover)
Urtica spp. (Stinging Nettle)
Veratrum spp. (False Hellbore). V. woodii in Illinois 
Vicia spp. (Common Vetch, Hairy Vetch, Narrow leaved Vetch, Purple Vetch and Broad Beans)
Wisteria spp. (Wisteria)
Xanthium strumarium (Cocklebur)
Zigadenus spp. (Death Camas)

For an Excel spreadsheet with a list of poisonous plants, click here

See the following:

Wikipedia - Poisonous Plants.  An extensive list here.

Hardin, J. W. and J. M. Arena.  1969.  Human poisoning from native and cultivated plants. Duke University Press, Durham, NC. 

Of course, any number of plants found in the Plant Biology Greenhouse could be cultivated in your house given the right growing conditions.  But that is exactly the issue - do you have the right growing conditions for the particular plant?  The most common problems encountered with cultivating plants indoors are 1) insufficient light, 2) dry air, and 3) improper watering. To be a successful indoor gardener, it doesn't hurt to look up the growing conditions that are optimal for your plant(s).  And be observant, such as watching how many days it takes for a pot to go from wet to dry (the finger test is good!).  So, for those who think they have a brown instead of a green thumb, the list of plants below is meant for you!  With just a little attention to their needs, these plants will thrive in most indoor environments.

1.  Araceae.  The arum family includes some of the most resilient plants known to man!  The native habitat where they grow is the tropical forest understory, so they are adapted to low light conditions.  Here are some real survivors:

• Epipremnum pinnatum cv aureum (previously Scindapsus aureus).  The Golden Pothos can root in water and probably grow in just water for months at a time!  Given some potting soil and a reasonable amount of care, it will grow very long vines with attractive variegated leaves.  I have seen them in office conditions, with just fluorescent lighting, grow to over 30 feet in length!
• Philodendron spp. These were some of the first houseplants to made commercially available.  Many species exist.  The ones with the dark green leaves survive best under low light conditions.
• Anthurium ssp. This is a large genus with hundreds of species and many hybrids and cultivated varieties.  Culture is similar to Philodendrons.
• Dieffenbachia spp.  Several species of Dumbcane are cultivated, such as D. amoena (Giant Dumbcane) and D. picta (Spotted Dumbcane).  All have large, variegated leaves and thick, cane-like stems (hence their common names).  

2.  Ruscaceae.  The houseplant members of this family used to be classified in Liliaceae, but the lily family was "split" into numerous smaller ones to better reflect relationships.  

• Sansevieria spp. The most commonly seen species is Sansevieria trifasciata which goes by several curious common names, Mother-in-law-tongue, Snake Plant, or Lucky Plant.  The first two names describe the overall appearance (I guess!?) and the last is appropriate given its cultural requirements.  This flowering plant is probably the most abuse-proof species on the planet!  You could literally put it in your closet for two weeks, never water it, and when you took it out, it would still be alive - and may not look too different from the day it went into solitary confinement!
• Dracaena spp. (Dragon Tree).  The common species seen are D. deremenis 'Warneckei' (Striped Dracaena), D. fragrans var. massangeana (Cornstalk or Corn Plant), D. marginata (Madagascar Dragon Tree).  Many of these come in variegated and non-variegated varieties.  One type, D. marginata 'Tricolor', is called Rainbow Tree because it has beautiful green, pink and yellow stripes on the leaves.

3.  Succulents.  Because these plants are adapted to xeric conditions, they do very well with little watering.  This is good for those who tend to forget about plants in the window sill.  In fact, some of these plants will do worse if watered too much as opposed to too little.  Under Special Topics is a separate category for Cacti and Succulents.  Note the main three families we are considering here are Cactaceae, Euphorbiaceae, and Crassulaceae.

4.  Spider Plants.  The genus Chlorophytum, specifically C. comosum and its variegated variety, are very often seen as hanging baskets in homes and businesses.  These plants are prolific, forming new plantlets at the tips of pendant stolons. This is why you should never have to pay money for this plant - somebody will have one with "babies" that you can get for free. This genus used to be classified in Liliaceae, but is now placed in Agavaceae along with Agave.

5.  Commelinaceae.  Many members of this family are easy to grow indoors.  These plants are for the enthusiast who may tend towards overwatering the plants, for indeed these plants don't mind!  Here are some commonly seen members of this family:

• Tradescantia fluminensis including its variety 'Variegata'.  Speedy Henry is a fast-growing plant!Tradescantia pallida (used to be called Setcreasea purpurea) - the Purple Heart Plant.
• Tradescantia sillamontana (White Velvet). Beautiful fuzzy leaves for those who don't want a pet of the vertebrate variety.
• Tradescantia zebrina (used to be called Zebrina pendula) - the infamous "Wandering Jew Plant".
• Dichorisandra thyrsiflora (Blue Ginger) is really not a ginger, but its leaves superficially resemble this plant.

There is probably no other group of plants equal to orchids in stimulating people's passion!  Nature has produced infinite varieties of shape and color in their flowers, but this is just the beginning.  Because genetic incompatibilities are weak among orchid genera, the horticulturalist is able to not only make successful crosses between species in a genus, he or she can also cross between genera.  

With 880 genera and over 22,000 species, the orchid family is second in size only to Asteraceae. 

Brassavola cucullata 
Brassolaelia ‘Richard Mueller’. Intergeneric hybrid.
Cattleya Blc. Memoria Crispin Rosales 'Victory'
Cattleya ‘Confetti Cocktail’
Cattleya harrisoniae 
Cattleya intermedia ‘Alba’
Cattleya intermedia 
Cymbidium hookerianum 
Dendrobium sonia near ‘Royal Pink’ and ‘Sakura Pink’
Dendrobium ‘Miss Singapore’
Dendrobium near ‘Sayala minis’
Encyclia adenocarpa
Epidendrum ibaguense
Epidendrum monterratense. Possibly this species.
Ludisia discolor
Oncidium spacelatum
Oncidium varicosum 
Oncidium ‘Gower Ramsey’
Oncidium sp. A hybrid with O. maculatum as one parent.
Phalaenopsis ‘Brother Mason Caldwell’
Phalaenopsis ‘Sogo White’
Phalaenopsis ‘Brandy Parfait’
Prosthecea cochcleata
Schomburgkia tibicinis
Vanda
Vanilla planifolia