Teaching Collection – James G. Kaskey Memorial Park

The Department of Biology Greenhouses at the University of Pennsylvania houses the official teaching collection for the department.

Our collection exhibits three different categories: plants representing different evolutionary pathways, those that demonstrate unique adaptations, and plants that are used as food, spice, and medicine crops.

Our accessions are comprised of 38 orders, 70 families, 163 genera, and 230 species.

View the collection:

Evolutionary Pathways

A terrarium houses several varieties of bryophytes and lycophytes.
Ferns evolved from lycophytes about 360 million years ago.
An up close view of fern spores, the reproductive method used by all ferns, fern-allies, lycophytes, and bryophytes.
Staghorn ferns, Platycerium bifurcatum, produce two kinds of fronds: foliar which photosynthesize and produce spores, and basal that trap organic matter to source nutrients.
Psilotum x intermedia, the whisk fern, is a fern ally. Like ferns it has a vascular system and reproduces via spore; it differs, in part, by not having any true leaves, relying on its flattened stems for photosynthesis.
Our Karoo cycad, Encephalartos lehmannii, is the oldest plant in the greenhouse, well over 100 years old. It is a gymnosperm, producing a naked seed.
Podocarpus macrophyllus, the yew plum pine, is also a gymnosperm producing fleshy berry-like cones.
Plants can be either monoecious (having all reproductive parts on the same plant) or dioecious (having pollen bearing and seed bearing parts on different plants). This Podocarpus macrophyllus is dioecious, with the pollen bearing cones visible.
Angiosperms evolved from gymnosperms. They are the most diverse group of plants, reproduce by flowers, and develop seeds from the ovary.
Angiosperms can be divided into two further groups, monocotyledons and dicotyledons. The difference between them is if the seed contains one embryonic leaf (monocots) or two (dicots). Monocots include over 10 plant families including grasses and palms, as seen here.

The plant kingdom has been evolving for approximately 1.5 billion years. Single-celled algae evolved into bryophytes (mosses) about 500 million years ago. These organisms are land dwelling, non-vascular, and do not produce flowers or seeds, instead reproducing via spores. About 420 million years ago bryophytes advanced into lycophytes (similar to mosses in many ways except they have vascular systems) and then ferns. About 350 million years ago gymnosperms, the first plant group to have true seeds, which are held in cones, evolved. The most recent evolutionary advancement were angiosperms, flower and seed bearing plants, which evolved about 150 million years ago.

Unique Adaptations

The Caribbean spider lily, Hymenocallis caribaea, 'Variegata' is a bulbous perennial that has adapted to be able to grow completely submerged in water.
Myrmecophytes are plants that have a symbiotic relationship with ants. The plants evolve to have structural adaptions that provide food and/or shelter to the ants in exchange for pollinator, seed dispersal, herbivory defense, and nutrient deposition.
A hollow "pod", formed by modified leaves of the ant plant, Dischidia pectinoides, creates a habitat and a place to store food for the ants.
The bullhorn acacia, Vachellia cornigera, provides a habitat for ants in its hollow thorns and produces protein, sugar, and lipid rich Beltian bodies at the tips of its leaves as food.
Monstera deliciosa leaves have holes (fenestrations) so that they can grow larger, capturing more diffused light in the dense rain forest, where they grow.
Carnivorous plants have developed an adaptation to be able to catch and digest insects for nutrients. This allows them to live in habitats with nutrient-poor soils, where most plant would not be able to survive.
Passive carnivorous traps, seen in Nepenthes spp., Sarracinea spp., Heliamphor spp., and Cephalotus spp., lure prey into the modified leaves (seen here as a pitcher). They cannot escape the slippery interior and are digested by an enzyme.
Semi-active carnivorous traps, as seen here in Drosera spp. and Pingulica spp. lure insects with their sheen. After the insects get stuck, leaves curl around the insect, which are then broken down by a digestive enzyme, allowing the plant to absorb the nutrients.
Active carnivorous traps, seen in Dionaea spp. and Utricularia spp., move quickly to trap their prey by snapping their leaves closed or sucking insects into an underwater bladder. This requires a lot of energy from the plant.
Epiphytic plants do not grow in the soil. Instead, they grow on the surface of other plants and get their nutrients from water and decomposing debris that accumulates around them.
Tillandsia usneoides, Spanish moss, is a staple of the landscape in the American South. It is epiphytic and gets all of its water and nutrients from the air and the morning dew.
Caudices, as seen on this Ipomea platens, are modified stems that often develop as a means of water storage for plants growing in arid environments.
Cacti and succulents have adapted to arid climates and intense sunshine by finding ways to increase water storage and preservation and use CAM photosynthesis which allows plants to photosynthesize during the day and transpire after the sun goes down.
Many cacti and succulents have adapted to have fleshy leaves and stems as a way to store water.
Glaucous waxy leaf coatings, as seen on this Echeveria sp., reflects ultraviolet light to slow desiccation and preserve water.
Some plants reproduce by growing plantlets, which will eventually drop off of the leaves and root into the soil beneath the parent plant. This adaption gives Kalanchoe spp. its common name, mother of thousands.
Plants develop a number of adaptions to prevent herbivory. Spurge species, like this Euphorbia cotinifolia, develop a toxic latex-rich sap.
Some plants, such as Geranium spp., produce strongly scented or acrid oils in their foliage to keep animals from eating them.
Another way plants defend themselves from being eaten is by growing thorns (modified branches), spines (modifies leaves or stipules), or prickles (an outgrowth of the epidermis).

Living organisms around the world adapt to their often hostile environments; and plants are no exception. Our collection highlights plants that have adapted to challenging environmental conditions such as low nitrogen levels (carnivorous plants), extremely hot temperatures (cacti and succulents), high plant competition (epiphytic plants), and extremely wet conditions (aquatic and marginal plants). There are also plants on display which show adaptations in order to have a symbiotic relationship with other organisms within their ecosystem.

Food and Medicine Crops

Flowers of Piper nigrum, black pepper, will develop into fruits, which are then dried and used as a spice.
Vanilla is the seed pod harvested from the orchid Vanilla planifola.
The starchy roots of Manihot esculenta 'Variegata' (tapioca and cassava) are important food sources for people in tropical climates.
Taro, Colocasia esculenta, corms are an important starchy food source in much of Southern Asia, Oceana, and Africa.
Fruit of the coffee plant, Coffea arabica, are fermented and roasted to create the beloved morning drink.
Opuntia humifusa, the prickly pear, is a food native to North America. Both the fruits and pads are eaten after the spines are removed.
The blooms of passionflowers, Passiflora spp., develop into tangy and sour fruits.
Monstera deliciosa fruits are eaten when ripe, tasting like a sweet fruit medley.
Both the leaves and the fruit of the lime leaf, Citrus hystrix, are popular ingredients in Southeast Asian cuisine.
Blooms of the pink banana, Musa velutina.
Several weeks later these small, fuzzy, pink bananas develop on Musa velutina.
The foliage of shell ginger, Alipinia zerumbet 'Variegata', is used in Chinese and Japanese cooking and herbal teas.
Aloe vera's gelatinous leaves are used medicinally to soothe skin ailments.

One way that humans connect with plants is through their use in food and medicine. Our collection holds a number of plants whose fruits, roots, leaves, seeds, and bark are important crops from around the world. These crops are prepared as produce, herbs, spices, and medicine.