Part 4

This is but one of twenty or more species of Penstemon found in Colorado. Some, such as _Penstemon angustifolius_, with its azure blue flowers, grow on the plains. A few are dwarf species of the sub-alpine zone such as _Penstemon harbourii_. Every zone and every section has its quota, and they range in color through all shades of lavender, blue, purple, and even red. In details of flower structure, as well as in size, they vary considerably. All of them, however, have a tubular corolla of some shape, terminating in five lobes, divided into two groups, giving them a two-lipped appearance. From this their relationship to garden snapdragons is apparent. In the penstemons, also, the topmost of their five stamens is sterile and often tipped with a little brush of hairs. This gives them the name of beardstongue.

Composite Family Gaillardia, _Gaillardia aristata_, PURSH

Flower head, 3 inches or more across, is formed of a central red disk made up of many minute tubular flowers (florets), surrounded by an outer circle of long flat golden rays cleft at tips into 3 teeth. Plants are 2 feet or more high of several rough stems usually erect, but sometimes contorted. The dark green leaves are lance-shaped and rough. Grows in foothills. Blooms June-July.

Do you have one just like this in your garden? Cultivation has changed the gaillardia less than it has most native plants. It was born a handsome, showy flower. There is charm in its notched rays and in the way the red of the central disk flowers runs outward into the gold of the rays, as though the painter had been careless with his brush and lavish with his colors. It grows far beyond the limits of Colorado. In the rough breaks of the Montana hills several separate plants will spread out and interweave as a colorful mass, giving it there the name “blanket-flower.”

Composite Family Rabbit Brush, _Chrysothamnus nauseosus_, H. AND C.

Individual flower heads are about ¼ inch across and double that in length, each formed of a dozen or more tubular bright gold florets closely compressed at their bases into a green involucre. Numerous such heads are clustered loosely together into round-topped groups (cymes) at the ends of stems and branches. Plant is a wide-branching, woody shrub 2-4 feet high with small, green-gray, linear leaves. Grows on dry plains and lower foothills, especially common in western Colorado. Blooms September-October.

Most of the better known composites have spreading rays—each of which is really a flower, though usually sterile—surrounding a disc of less conspicuous tubular flowers, these latter being normally the fertile ones. Sunflowers are familiar examples. Throughout some genera of this great family, and in various species of additional genera, the rays are totally absent. Rabbit brush is one of the composites whose flower heads have no rays. They are showy only because so many of them cluster together, and because each small flower contributes a speck of bright gold. They are distinctly plants of desert lands, and in the fall season each big clump is a perfect mound of color. As winter nears, the color pales and fades, though flowers hang on a long time. Rabbit brush is not a sagebrush, even though both grow on the same dry plains and both are members of the composite family.

Composite Family Easter Daisy, _Townsendia sericea_, HOOK.

Flower heads, 2 inches across, are formed of about 30 white rays, slightly striated and indented at the tips, surrounding a disc, about ¾ inch in diameter, of numerous tubular gold-colored florets. Plant is about 3 inches high and carries one or several flower heads right on the top of a spreading tough root crown from which also rise numerous, narrow, linear leaves about 2-3 inches long. Grows on grassy plains, and foothills. Blooms April-May.

These are among the very earliest of the plains flowers. Their typical occurrence is as isolated plants, one here and one there between grass turfs in areas of rather tight prairie sod. They are so low and compact that they are not easy to find, even though their beauty well justifies the search. Spring has come when Easter daisies are out, even though the plains are still clad in winter gray with only a faint suggestion that in time the range will be green. Several other members of this daisylike genus are found in the foothills and plains. One of the commoner of these, _Townsendia eximia_, is easily distinguished by its short spreading branches which carry a few leaves.

Composite Family Showy Fleabane, _Erigeron speciosus_, C. FONG

Flower head, 1½ inches across, is composed of about 200 narrow rays of brilliant lavender color, surrounding a button-like center ½ inch in diameter, of numerous, bright-gold, tubular florets packed closely together. Plant is 1½ to 3 feet high, freely branching, with numerous flower heads; leaves oblong or oval 2-3 inches long. Grows in shady places, rich moist soil, montane and sub-alpine zones. Blooms late July-September.

As the season advances, these aster-like flowers become the most conspicuous color notes in our high-altitude aspen groves. They come after early flowers are gone and bloom with a profusion unknown to most shade-loving plants. Before they too are gone a leaf here and there on the geranium plants in these same places will have turned bright red; on the ground, ivory colored puff-balls will be ready to discharge their clouds of brown spores, and the very first of the aspen leaves will have turned yellow and be drifting down. Showy fleabanes may linger to catch the first fall snows. Another of the many members of this genus, _Erigeron trifidus_, grows on the plains and brings out its small white blossoms in late April when it may catch the last spring snows.

Composite Family Alpine Sunflower, _Hymenoxys grandiflora_, PARKER

Flower head is 3 to 4 inches across, the central disk, an inch in diameter, made up of over a hundred tiny, tubular, golden florets, surrounded by about 30 bright yellow rays which are flat and notched at the outer end. Plant is 5 to 15 inches tall of one or several woolly stems, with leaves divided into several narrow lobes. Grows on alpine slopes. June-July.

This woolly-stemmed, dwarf sunflower, sometimes called old-man-of-the-mountains, or sun-god, is a startling surprise for the newcomer to our above-timberline tundras. One expects smaller more timid flowers here, and so at first the big bright faces of these plants seem out of place. Then we come to love them for their gay defiance of tough growing conditions and think of them as the proper guardians of high windy places. Whole colonies of them will be found with all the flower heads faced in the same direction. This will be a direction from which they receive strong light, and is a form of heliotropism. The stems, however, do not twist through a full half circle each day to follow the sun.

Composite Family Thistle, _Circium undulatum_, SPRENG.

Flower heads, 1½ to 2 inches broad, are solitary at the ends of stems and branches, and made up of numerous (100 or more) rose-colored, tubular florets fluffing out widely at their tops and grouped tightly together at their bases into an involucre made of many little, overlapping green bracts. Plant is about 3 feet tall with gray-green deeply cut leaves; stem and leaf ribs armed with prickles. Grows on plains, extending into foothills. Blooms May-September.

Thistles of some sort are found in all parts of Colorado. Above timberline they take on grotesque shapes. In one, high-altitude thistle, _Circium hookerianum_, the whole woolly top of the plant, formed of compressed leaves and inconspicuous flower heads, bends over to resemble the head and neck of some shaggy animal. In our sub-alpine hay meadows a different species, _Circium drummondii_, may spread flat on the ground with no main stem and keep its flower heads so low that the mowing machine goes right over it catching only tops of a few leaves. On the plains are other species with shaving-brush-like flower heads. In spite of the prickles on their leaves and stems, horses nip off the flower heads and eat them with relish. Donkeys and mules seem to like them even better.

CLASSIFICATION OF PLANTS

All plants are related to each other in the sense that every one of them is descended from a common primitive uni-cellular life form which came into existence on this planet millions of years ago. As the remote progeny of that ancestral cell, or group of cells, became scattered over the earth and faced diverse conditions, which in turn changed with the ages, these millions of related organisms exhibited profound changes such that the differences in form, size and structure have become more noticeable than are the badges of common inheritance. This is the process called Evolution. Changes are established so slowly, however, that the immediate descendants of any particular plant, or the offspring from cross-pollination within a closely related group, will continue for many generations to be substantially identical in structure with the parents. As long as substantial identity in structure exists, all of these individual plants form a single “species.” As these species are discovered, botanists give each of them a Latin name. Within Colorado over 2000 such separate species of flowering plants are known. Minute variations such as color of petals or degree of hairiness of leaf or stem are treated as “varieties” within the species.

Many thousands of these substantially identical plants may be found scattered over parts of a state, or over several states, or even throughout a life zone area comprising parts of several continents. Within the life zone favorable to them, the only geographical limits seem to be those affecting distribution of live seed.

In the search for plants, many different species are found, either in the same or more often in different localities, in which the resemblances are close; in fact many parts are almost identical, but persistent differences are also present. A common ancestor several hundred or several thousand years back may have existed, but evolutionary changes have brought noticeable differences in the respective descendant groups. If the changes are not too great, especially if the mechanisms of reproduction have not been so greatly changed as to make cross-pollination totally impossible between plants of the several species, these related species, wherever they may have been found, are said to comprise a “genus.” To this, also, a Latin name is given. _Lillium_, for example, is the generic name of all true lilies everywhere; _umbellatum_, however, is the specific name of the group to which our Colorado mountain lily belongs; and “_Lillium umbellatum_” is the full name of the plant shown on page 10.

Still greater differences in plant and flower structure are found, coupled, however, with strong resemblances in significant parts of the structure. This has led to grouping a considerable number of genera together into a “family.” Latin names also are given to the families. For these names there are, in most cases, well established English equivalents which we have used here without repeating the more technical family name. Within each family all genera and each species of every genus will exhibit strong resemblances in the mechanism of seed production, and the general pattern of the organs of reproduction will be recognizably similar. For example, all species in the rose family (with very few exceptions) have numerous stamens arranged in whorls; they also have a calyx formed of five sepals joined together at the base.

Other groupings, such as “Orders” comprised of several families, or “tribes” composed of several genera within a family, are used by botanists, but for the purposes of this booklet we have used only the names of families, genera and species.

To the amateur one of the most interesting phases of plant classification is the way in which, as we pass from one life zone to another, or from one part of the state to another part within the same life zone, we find that a plant species which we have observed at one spot, is replaced, at another, by a different species within the same genus. We find our white mariposa, _Calochortus gunnisonii_, on the east side of the mountains, then, in flat clay plains in southwestern Colorado, we find the sego lily, Calochortus nuttallii, which is a similar, but quite distinct mariposa with cream-colored petals and a crooked, much shorter stem. Beyond the boundaries of Colorado numerous other species of Calochortus are found, all of them different from ours, but all of them quite obviously mariposas.

HOW PLANT POPULATIONS MAINTAIN THEMSELVES AND SPREAD

Infant mortality is high and life expectancy short among the flowering plants. They not only struggle against extremes of climate, but they are the primary food of the animal kingdom, and so pursued by creatures that have the advantages of sight and locomotion. It is only by marvelous fecundity and by ingenious devices for seed dispersal that plants maintain their position on the earth.

The first objective of every plant is to produce fertile seed in as large a quantity as the supplies of food and moisture and the length of season will permit. Pollination, which brings about the merging of the male and female cells, is essential to seed production. The majority of plants combine in a single flower stamens which carry in anthers on their tips the male element pollen and one or more pistils which hold at their base ovaries containing the female cells. These ovaries are reached by the pollen through the style and the stigma at its tip. The flower may thus fertilize itself in most species, but cross-pollination from other plants of the same species makes for more vigorous stock. The showy petals and petal-like sepals, which draw our eyes to flowers, make the flower conspicuous also to bees, moths, and even birds which act as pollen bearers. Other lures to this same end are fragrances and nectar. The detailed mechanisms by which the various plants increase the likelihood of cross-fertilization, within the brief period that any given set of cells is capable of fertilization, are numerous indeed and a fascinating study.

In most plants, seed develops and becomes fully ripe in a matter of weeks after fertilization has occurred. It is also commonplace for a single flower to produce a seed pod or other fruit which may contain hundreds of separate perfect seeds.

The next step is to scatter this seed over an area wide enough to reduce the risk of all of them perishing at once, and also wide enough to keep the survivors from competing too closely with each other for soil, moisture and sunlight. Here again fascinating devices come into play. Building each seed with a plume or bit of fluff at its tip so that it can be carried far by wind, is one of the commonest tricks. Other seeds float easily on water and so reach new sites. Other seeds invite being eaten by birds or beasts, and depend upon a fraction of them either being carelessly dropped before being swallowed, or having tough enough shells to resist digestion. Quite a number of plants produce seed pods which, when they become thoroughly dry split open with a jerk flipping seeds over distances of several feet. Finally there are the various burs and barbed seeds that are carried for miles by animals and by man.

Seeds thus become scattered over the earth, and so numerous and efficient are the devices of dispersion that in the course of years the seeds from a single plant colony, and from the successive new outlying colonies it founds, may become spread over miles of distance. Only a few barriers completely stop such spreading. Oceans, high mountains and broad deserts are the most effective barriers, but even they do not always stop every seed of every plant.

This spread of seeds pays little attention to life zone limits, or to such interference as rivers, hills or local barren areas may present. Over and past all of such minor obstacles the flow of seed rolls.

The final problem for the seed is how to germinate and become established in the place it lands. If that place is totally unsuitable for the particular species, the answer there is failure. Many seeds may invade a locality too dry for their development. In such a case, even if germination occurs, all such seedlings will die before a single plant matures. Heavy frost may act as a like absolute veto to other seedlings that venture too high in altitude or too far north in latitude for their own limitations. By forces such as these, each species of plant stays contained within limits beyond which it cannot become established, even though individual seeds may in great numbers invade impossible localities.

Mature plants may tolerate conditions which wipe out all tender seedlings of the same species. This leads to interesting patterns of plant distribution in semi-desert areas, such as occur in parts of Colorado. Once or twice in a century a series of two, three, or even five successive years may occur when the soil is moist and extraordinarily favorable to plant growth throughout weeks or months of the spring and summer. In these special times seeds that have invaded a usually hostile area may, if they have retained fertility, germinate, push their roots deep, and become so vigorous that when normal dry years follow these particular plants live on and thrive for the remainder of their lives, even though their own seeds fall on barren ground and the species maintains only a precarious or temporary foothold in the area.

Governed by forces such as these, and limited by competition with each other, plant species have for ages taken their places in the global economy and carried out their part of the commandment to be fruitful and multiply. Otherwise we and the animals we prey upon could not exist.

FLOWER FORMS

The four flowers sketched below with supplementary drawings of their separate parts, give only a small sample of the infinite structural variety found among flowering plants.

perianth segment stigma anther style ovary pedical stem Detail of stamen pollen anther filament

group of styles sepal group of stamens ovary pedical single sepal Detail of stamen

lobe of corolla sterile stamen anther stigma style sepal ovary calyx pedicel Details beard filament anther filament

(right half cut away and all other florets removed) bracts of involucre tubular floret receptacle ray floret stigma style stamen corolla tube ovary receptacle

PLANT PARTS

pedicel stem

pedicel bract scape

stem bulb

stem root crown or caudex

main stem tap root root

scape

LEAF FORMS

linear lanceolate ovate cordate

pinnate pinnately cleft bipinnate palmate

opposite alternate whorls

stem petiole stipule

BOOKS DEALING WITH COLORADO WILDFLOWERS

Field Book of Western Wild Flowers—Margaret Armstrong C. P. Putnam’s Sons, N. Y., 1915

Plants of Rocky Mountain National Park—Ruth E. Ashton Government Printing Office, 1933 Revised edition under same title—Ruth Ashton Nelson in press, 1953

Colorado Cacti—Chas. H. Boissevain and Carol Davidson Abbey Garden Press, San Marino, 1940

Rocky Mountain Flowers—Frederic E. and Edith S. Clements H. W. Wilson Co., N. Y., 1920

New Manual of Botany of the Central Rocky Mountains—John Coulter and Aven Nelson American Book Co., Chicago, 1909

Manual of the Plants of Colorado—H. D. Harrington Sage Press, Ft. Collins, Colorado—in press, 1953

American Wild Flowers—Harold N. Moldenke D. Van Nostrand Company, Inc., N. Y., 1949

Meet the Natives—M. Walter Pesman Denver, Colorado, 1943

Flora of Colorado—P. A. Rydberg Ft. Collins, Colorado, 1906

Flora of Rocky Mountains and Adjacent Plains—P. A. Rydberg New York, 1917

The Flora of Boulder County, Colorado—William A. Weber University of Colorado Museum

OTHER MUSEUM PICTORIALS

1. Nature Photography with Miniature Cameras—Alfred M. Bailey

2. The Story of Pueblo Pottery—H. M. Wormington and Arminta Neal

3. Stepping Stones Across the Pacific—Alfred M. Bailey and Robert J. Niedrach

4. Fossil Mammals—Harvey C. Markman

5. Nature Photography with High-Speed Flash—Walker Van Riper, Robert J. Niedrach and Alfred M. Bailey

6. Laysan and Black-footed Albatrosses—Alfred M. Bailey

7. The Hawaiian Monk Seal—Alfred M. Bailey

INDEX

A _Page_ _Abronia fragrans_ 14 Alpine forget-me-not 46 Alpine sunflower 55 _Anemone globosa_ 20 _Aquilegia coerulea_ 24 _Argemone intermedia_ 25 _Asclepias speciosa_ 43

B Bird-bill 41 Brook primrose 40 Bush cinquefoil 29 Bush morning-glory 44

C Cactus 35-36 _Calochortus gunnisonii_ 11 _Castilleja integra_ 49 Cattail Back Cover _Chimaphila umbellata_ 39 _Chrysothamnus nauseosus_ 52 _Cirsium undulatum_ 56 _Claytonia lanceolata_ 17 Columbine 24 _Cypripedium calceolus_ 13

D Deer clover 31 _Delphinium nelsonii_ 21 _Dodecatheon radicatum_ 41