Plant Glossary

Types and Habits of Plants

• Shrubs- woody plants having multiple branches, bushy, intermediate stature, and shorter than trees.
• Trees- woody, single-trunked, statuesque plants that grow into tall, multi limbed structures.
• Herbs or Forbes- small plants with soft, delicate stems, usually with annual or biennial growth cycles completed within 1 or 2 seasons.
• Grasses– plants having slender leaves and reproduce via underground rhizomes or seeds.
• Sedges and Rushes- often growing in water or in riparian zone
• Vines- plants that propagate outward and up with support., sometimes woody like grapes
• Cactus and Succulents- very common strategy to save water in the desert. Succulents are similar to cacti plants that have juicy, fleshy stems which retain moisture.
• Weeds- the term weed is pejorative, however foreign plants may often edge out natives

Roots

• Rhizome- are modified plant stems that grow horizontally near or below the soil surface.
• Stolon- a stem that grows along the ground surface and develops into a new plant at nodes.
• Bulbs- are specialized layers of rounded underground storage organs that store water and nutrients.
• Corms- are solid, swollen, underground plant stems (storage organ), like a bulb but with a distinct difference, they are one solid mass of stem tissue.
• Tubers- are swollen stems or roots with “eyes” (buds), like a potato.

Climbers and Creepers

• Climbers- describe plants which require a rigid support structure.
• Creepers- plants that spread horizontally with weak stems, and that grow along the ground.
• Vines- plants which have stems that climb or trail requiring a support structure.
• Lianas- are woody vines that climb on trees or require other supports.

Succulents

Succulent plants possess several specialized mechanisms to survive in arid conditions. They are capable of storing water within their leaves and stems, and they are covered by a waxy outer layer that effectively reduces moisture loss through evaporation.

Leaf Succulents

Leaf succulents, which include yuccas and agaves, often grow in a rosette pattern. This specific arrangement of leaves on the stem is designed to capture water and direct it down toward the plant’s root system. Stem succulents are typically shaped as cylinders or spheres, which is a structural adaptation that minimizes their surface area relative to their overall volume. Most stem succulents found across North America belong to the cactus family.

Cactus

Further evolutionary adaptations unique to the cactus family include the reduction of leaves into spines, which serve as protection and further reduce surface area. Additionally, they possess ribs that are capable of expanding or contracting like an accordion to accommodate variable amounts of water storage. Another critical adaptation is their specialized type of photosynthesis (CAM), which allows them to open their pores and exchange gases only during the night when temperatures are cooler. Cacti that have flat pads, such as the beavertail, strategically position their pads at angles that ensure the least amount of direct exposure to the intense summer sun. Similarly, the tops of barrel cacti are designed to minimize heat absorption by naturally bending toward the south.

Grasses, Rushes and Sedges

Further evolutionary adaptations unique to the cactus family include the reduction of leaves into spines, which serve as protection and further reduce surface area. Additionally, they possess ribs that are capable of expanding or contracting like an accordion to accommodate variable amounts of water storage. Another critical adaptation is their specialized type of photosynthesis (CAM), which allows them to open their pores and exchange gases only during the night when temperatures are cooler. Cacti that have flat pads, such as the beavertail, strategically position their pads at angles that ensure the least amount of direct exposure to the intense summer sun. Similarly, the tops of barrel cacti are designed to minimize heat absorption by naturally bending toward the south.

Weeds

• Native plant- an indigenous plant that has developed over millennia in a specific region. Our native bees, butterflies and birds are literally made from these plants. These plants are adapted to our local environmental conditions, rainfall patterns, and soil conditions. Native plants are not considered invasive plants no matter how vigorous they may become!
• Non-native plant- are plants introduced by humans (intentionally or accidentally) to a new habitat where it was not previously found. Not all non-native plants are invasive, non-native plants are introduced to new places, they can reproduce or spread readily without continued human assistance.
• Naturalized plant- are non-native plants not requiring human help to reproduce and maintain itself over time in non-native area. Even though their offspring reproduce and spread naturally, naturalized plants do not become native plants over time.
• Exotic plant- are plants not native to our continent, i.e. plants from Europe are exotic in North America.
• Translocated plant- is a plant which is not native to the portion of the continent where it is now found, such as California Poppies in New England.
• Invasive exotic plant- are plants that are non-native and able to establish on many sites, grow quickly, and spread to the point of disrupting plant ecosystems. Examples of invasive exotic plants include annual ryegrass, Bermudagrass, Chinese privet, Crimson Clover, Chinese Tallow and Japanese Honeysuckle.
• Noxious Weeds- any plant (invasive, non-native) designated by a Federal, State or county government as injurious to agriculture, public health, wildlife or property. Note: USDA APHIS maintains a list of federally recognized noxious weeds. It is illegal to import Federally listed noxious weeds or transport them across state lines. Some states or counties maintain lists and have passed laws regarding responsibilities for their control except for Connecticut.
• Weed- a plant considered undesirable and growing where it competes with desire, cultivated plants

Duration

• Annuals- vegetation that complete a life cycle (seed to seed) in one growing season. In the desert, most spring flowers are annuals and dependent on rainfall.
• Biennials- plants that complete the life cycle within two seasons, the first year is vegetative growth with flowering and seeding the second. True biennial plants (taking two years to complete their life cycle) are rare in the Mojave Desert because erratic rainfall favors fast-cycling annuals or long-lived perennials.
• Perennials- plants that grow for three or more years, producing flowers and seeds each year. Mojave winter perennials time their growth and blooming cycles to coincide with the region’s cooler temperatures and seasonal winter rains.
• Evergreens- trees which do not shed leaves at the end of the growing season and retain leaves year round.
• Deciduous- trees that shed leaves at the end of the growing season.
• Drought Deciduous- A drought-deciduous plant is a specialized desert or dry-climate plant—such as the brittlebush, ocotillo, or palo verde—that sheds its leaves during hot or dry periods to save water.
• Herbaceous Perennials- are ‘non-woody’ perennial plants that die back in the winter, returning in the spring.
• Woody Perennials- shrubs and trees that maintain a ‘living’ woody stem at the end of the growing season.

Stems, Trunks and Petioles

Stems and petioles are both plant stalks, but they have different jobs and places on the plant. A stem is the main body of the plant, a petiole connects a leaf to the stem, and a node is where they join. Stem adaptations in the desert include:

• Water storage- Swollen, fleshy stems act as reservoirs to hold precious moisture from rare rainstorms.
• Stem photosynthesis- Stems turn green and take over food production when leaves are reduced or absent.
• Waxy coatings- A thick, outer layer minimizes water loss from harsh sun and dry winds.
• Ribs and pleats:- Ridges allow stems to expand safely when absorbing water and provide cooling shade
• Thorns- to avoid predation of leaves.

Leaf Arrangement

Leaf arrangement is a surprisingly good way to differentiate similar looking plants.

• Alternate- Leaves that are staggered, not placed directly across from each other on the twig
• Opposite- Leaves are directly across from each other on the twig
• Whorled- Three or more leaves equally spaced leaves at one node
• Basal- the part of a plant stem from which one or more leaves emerge, often forming a slight swelling or knob

Leaf Shape

If the shape, color or edge of the leaf is unusual, it can often provide a definite identification. All the names don’t matter, just something to plug into the search engine. Lanceolate and Cordate are two of the most useful shapes.

Flowers

First of all, in the larger world of plants, not all produce flowers. Non-vascular plants don’t. And within the category of vascular plants, non-seed producing plants don’t make flowers either. Within the category of seed producing plants, there are two groups: gymnosperms and angiosperms. Angiosperms produce flowers; gymnosperms don’t. Even though that narrows it down quite a bit, we are still dealing with a very large group of plants. The complexity doesn’t stop there, of course. Memorizing the names of flower structures and recognizing them on each flowering plant would be easy if every flowering plant had all of the same structures and if all structures existed on each flower. However, this is not the case. Depending on the flower you are looking at, some structures may be absent and some may have additional structures that are not common ones. Also, some plants have inflorescences that appear as a single flower but are actually a collection of many smaller flowers (or florets), like plants in the sunflower family (Asteraceae) for example. Additionally, look very carefully in the desert for flowers since many are tiny. To help you, the site has a photo grid of flowers that can be narrowed down by color. On a practical basis, if you count the number of petals and note the color of the flower, you will likely have a small number of options within a given geographical area.

Fruit

Mojave Desert plant fruits include prickly pear tunas, Mojave yucca pods, and Joshua tree capsules. These native species produce unique, specialized fruits adapted to extreme arid conditions and help with identification when the plant is not flowering. Because there are few animals to spread seeds in the desert, many of the seeds will be dispersed by the wind with achenes or pappus. Desert grass species can often be identified by seed types. Examples include:

Wildflower and Annual Seeds

• Desert Chia (Salvia columbariae): Tiny, nutrient-dense seed pods prized by local wildlife and humans alike.
• California Poppy & Arizona Lupine: Colorful spring annuals that rely on heavy rain to break hard seed coats.
• Desert Marigold & Goldfields: Prolific self-seeding bloomers that blanket sandy washes and flats.

Perennial Shrub and Bush Seeds

• Brittlebush (Encelia farinosa): Small, dry achenes that disperse easily on the wind near rocky slopes.
• Creosote Bush (Larrea tridentata): Woolly-coated capsules protected by dense hairs to survive extreme heat.
• Desert Globemallow (Sphaeralcea ambigua): Tiny kidney-shaped seeds housed in dry capsules.

Native Grass Seeds

• Indian Ricegrass (Achnatherum hymenoides): Plump, starchy grains historically used as a food source.
• Big Galleta & Bush Muhly: Tough bunchgrass seeds adapted to summer monsoons or winter moisture.