Plant Briefs

Cercocarpus montanus Raf. (Rosaceae)

Mountain Mahogany

Mountain mahogany is one of the most prevalent shrubs in the foothills near Fort Collins. It has a conspicuous persistent style which is long and plumose. When dried out, this style helps to "self-plant" the seed by orientating it into the soil and then, when blown by the wind, helps to drill it into the ground. Colorado has three species of Cercocarpus, which have different ranges all over the state. Mountain mahogany shrubs form thick stands and occur in elevations from 1500 to 2400 meters. Mountain mahogany grows best on thin soils, and has the ability to fix nitrogen.

Cleome multicaulis Sesse & Mocino ex DC.

Slender Spiderflower

A delicate and attractive plant, this pink-flowered annual inhabits saline or alkaline soils at the edge of many of the wetlands of Colorado's San Luis Valley. A member of the caper family (Capparaceae), slender spiderflower (Cleome multicaulis) is smaller in stature and much more restricted in its distribution than its common relative, Rocky Mountain beeplant (C. serrulata).

Members of the caper family closely resemble mustards (Brassicaceae), but, unlike mustards, have stamens (six in number) that are all of one length. C. multicaulis has four petals which are clustered towards one side of the flower. The inflorescense is distinctive and quite attractive, with a single inflorescence containing both light pink and dark rose flowers. As flowers are pollinated and begin to mature, they undergo a color change which may serve as a pollinator "cue" that nectar rewards are no longer forthcoming.

Leaves of this species are trifoliate, with linear leaflets that often fold along the midrib. Stamens (unlike those in the more common C. serrulata) do not exceed the petals in length. The ovary matures into a narrow capsule (about 10mm long) at the end of a stalk (stipe). When the tiny (1mm) seeds are dispersed by wind and water, the capsule breaks open and the outer frame (replum) of the capsule persists.

Although herbarium collections of C. multicaulis exist from Texas, New Mexico, Arizona, and Mexico, more recent populations have been located outside the San Luis Valley only in southcentral Wyoming. Draining of wetlands throughout the southwest is thought to have drastically decreased the amount of available habitat for this species.

Populations in the San Luis Valley appear to thrive in the saturated soils created by waterfowl management regimes on Valley public lands. Fluctuations in population size from year to year can be considerable, however, and a "bank" of dormant seeds in the soil helps buffer this annual plant against extremes in environmental variation.

Because of its highly restricted distribution, slender spiderflower was previously afforded statutory protection as a Category 2 (C2) species under Federal law, indicating that additional information was needed to determine whether the plant should be listed as Threatened or Endangered. Although the Category 2 designation no longer exists for any plant or animal taxa, this species remains a management concern for State and Federal agencies in areas where it is found.

Visitors to San Luis Valley wetlands wishing to locate this slender plant should search in July and August for dense populations forming a hazy band of pink flowers at wetland edges, in a region between rushes (Juncus sp.) and alkaline-tolerant greasewood (Sarcobatus vermiculatus) shrubs. Russell Lakes State Wildlife Area (9 miles S of Saguache) and Blanca Wetlands (N E of Alamosa) both have several populations accessible to the public after waterfowl nesting season has ended (July 15 of each year). Contact the CSU Herbarium for more specific details. Care should be taken in visiting populations as the delicate plants are easily trampled. Smaller and more remote populations can be found (along with many other delights) at Mishak Lakes Preserve, a recently acquired Nature Conservancy tract; contact The Conservancy's San Luis Valley office in Saguache (719 655-2772) for further details on visiting this site.

Picea pungens Engelmann

Colorado Blue Spruce

Blue spruce is one of the most stately and attractive tree species in Colorado. It is this grandeur that has compelled residents to select the species as the State tree for both Colorado and Utah. The blue spruce typically reaches heights of 30 m, but individuals as much as 50 m tall have been recorded. The trunk normally reaches 1.5 m in diameter at maturity. The canopy is dense and conical when young, but becomes more ragged-pyramidal with age. Its branches are slightly to strongly drooping. The leaves are 1.6-3 cm long, four-angled in cross-section, rigid, blue-green, and frequently glaucous.

"Blue", in the common name blue spruce refers to foliage color and its whitish waxy coating. The specific epithet "pungens", meaning "sharp", describes the nature of the needle-shaped leaves.

The natural habitat of the blue spruce is in the mid-montane forests of Arizona, Colorado, Idaho, New Mexico, Utah, and Wyoming between 1800-3000 m (ca. 5900-9800 ft.). The tree prefers moist soils and is especially prevalent along streams and mountain valley bottoms. Blue spruce belongs to the pine family (Pinaceae). Its close relative is Engelmann spruce (Picea engelmannii) which reaches higher elevations up into the alpine zone. The two species overlap in the subalpine zone and interspecific hybrids have been found.

The blue spruce was first put into cultivation in 1862 and has since become a favorite tree of horticulturalists and landscapers.

Nuphar luteum Sibth. & Sm. ssp. polysepalum (Engelm.) Beal

Yellow Pond-lily, Spatterdock, Cowlily, Pond Lily

One of the most beautiful aquatic plants in Colorado is the Yellow Pond-lily. These plants arise from thick underground rhizomes or rootstocks which anchor the plant to the bottom of a body of water. These rootstocks are comprised of a very porous tissue that also helps the plant to exchange gas while underwater. The leaves are large and float on the surface of the water. They are also heart-shaped, and can reach up to 16 inches in length. The upper surface of these leaves is very thick and waxy, which acts to repel water off of the upper leaf surface. The leaf petiole can grow to an amazing 6 feet in length!

The flowers of Nuphar are perhaps the most impressive of all the aquatic plants in Colorado. Arising out of the water in late summer, these large, beautiful flowers are yellow in color, but can be tinged with tints of orange or red. The fruit is equally large and pod-like, containing a mass of seeds.

In North America, Yellow Pond-lily is distributed from the Black Hills of South Dakota to Alaska, and farther south to Colorado and Utah. It is most common in high mountain lakes and ponds in the Rocky Mountains, and can sometimes be found up to timberline. It is a mystery why these plants occur in some lakes but remain absent from others with the same attributes.

Native Americans also used the Pond Lily as a source of food. In fact, the Pond Lily was a very important food source to the early Native Americans, especially in the Northwest. The rootstocks were baked until dry so that the hard, outer rind could be removed. Then, the spongy, inner contents were ground into a meal. The meal could then be used in various ways such as to thicken a pot of soup.

The seeds of the Pond Lily were likewise dried and then parched over heat so that the hard shell could be removed. The kernels could then also be ground into a meal and eaten.

Physocarpus monogynus (Torrey) Coulter

Rocky Mountain Ninebark, Colorado Ninebark

Physocarpus monogynus or ninebark is a beautiful shrub that is a member of the Roseaceae family, and makes a nice addition to a native landscape throughout the year. Ninebark grows 2-3 feet tall, and its bark is shed in layers, leaving several shades of brown. It is from this character that the name ninebark was derived - there are nine colors of bark present!

There are many other attributes of ninebark which make it a nice addition to the landscape year-round. The flowers of ninebark are white and quite attractive, and are grouped in small clusters. Ninebark flowers from June to July. The flowers last for approximately 5 days, and are followed by an attractive reddish-brown fruit. In addition, the leaves are palmately lobed and turn bright red in the fall.

Physocarpus monogynus is commonly found in the foothills to the subalpine zones on rocky slopes and in forest openings. In the landscape, it can be planted in full shade, and grows best in shady locations or areas without direct sunlight exposure. Not many shrubs prefer to grow in the shade, making ninebark a very useful shrub for landscaping. Ninebark can also withstand some exposure to the wind. It is best used when planted with 4-10 specimens grouped together.

Physocarpus monogynus hybridizes with another species of ninebark found in Colorado, Physocarpus opulifolius, where their distributions overlap. Physocarpus opulifolius is distinguished from Physocarpus monogynus by having larger leaves (3-8 cm long as opposed to 2-3 cm long) and leaves with a wedge-shaped base instead of a mostly heart-shaped base. However, when hybridization occurs, these characters can become intermixed. Physocarpus monogynus is more commonly found than Physocarpus opulifolius.

Pediocactus simpsonii (Engelmann) Britton & Rose var. simpsonii

Mountain Cactus; Simpson hedgehog cactus; snowball cactus

Pediocactus simpsonii or mountain cactus is a common and beautiful cactus you will find throughout Colorado. It is a globular type of cactus reaching up to 6 inches in diameter and is strongly tubercled. Mountain cactus flowers from early May to June. These flowers are born in the center of the cactus and are usually a brilliant pink, but can sometimes be whitish in color. Interestingly, the flowers are generally pink on the eastern slope and yellowish on the western slope plants. The flowers usually remain closed on cloudy days.

Mountain cactus is found throughout Colorado, from the foothills to the montane zone. Specimens have even been found at an altitude of 10,000 ft. at Monarch Pass on the western slope - hence the name mountain cactus! Mountain cactus usually grows in rocky soil on exposed ridges where it can receive the most sunlight.

Pediocactus simpsonii was first named by George Engelmann for army engineer James H. Simpson under the name Echinocactus simpsonii. Simpson led an expedition in Colorado, and Engelmann named the species "in honor of the gallant commander" of the expedition. The name of Pediocactus simpsonii was set forth by Britton and Rose, the genus name meaning from the plains (even though this cactus grows in the mountains!).

Pediocactus simpsonii (Engelmann) Britton & Rose var. minor (Engelmann) Cockerell or Pike's Peak cactus is found on the eastern slope, and as the name suggests is common on Pike's Peak. It too prefers a mountainous habitat in dry, rocky soil. It can be distinguished from P. simpsonii var. simpsonii by its smaller stature. The entire plant inlcluding the tubercles, spines, flowers, and seeds are smaller than those of P. simpsonii.

Pediocactus simpsonii and its variety minor are common in Colorado, and their bright pink flowers make an attractive addition to the Colorado landscape. Try locating a few of these charming cacti next summer!