The Monthly Orchid—a Letter to the Earth

… its broad extremity is folded over and backwards in a peculiar manner, so as to form a sort of shoe ... Hence arises the English name of Lady's Slipper. (photo by Matt Lavin).

Let me start by explaining how honored I was when Ms. Plantsandrocks asked me to contribute to her series about Orchids while she is traveling in The Dakotas. My knowledge of the family is vast, but I fear it may be a bit outdated. However, the heart-felt joy that I find in Orchids has not diminished, and I hope to share some portion of it with you. By the way, I was advised to write in a straightforward manner, as the eloquence of my day has gone out of fashion. I shall try my best in that regard, but can make no promises, being very much a man of my times. (1)

I believe some of you are acquainted with my book, Fertilisation of Orchids, described by Ms. Plantsandrocks in an earlier article. It was issued shortly after On the Origin of Species, with the intention of demonstrating that I had put much effort into finding evidence and case studies in support of natural selection. During the summer of 1839, and the one previous, I had been strongly drawn to the cross-fertilisation of flowers by insects, having come to the conclusion that crossing played an important part in keeping specific forms constant. I attended to the subject during every subsequent summer, my interest greatly enhanced by having read C. K. Sprengel's wonderful book, Das entdeckte Geheimnis der Natur.

The Secret of Nature in the Form and Fertilisation of Flowers Discovered, CK Sprengel 1793 (source).

My little orchid book cost me ten months’ work, but it was a sound investment. Since its appearance, a surprising number of papers and separate works on the fertilisation of all kinds of flowers have appeared; and these are far better done than I could possibly have effected. The merits of poor old Sprengel, so long overlooked, are now fully recognised many years after his death.

Let me move now to the Orchids, specifically the Lady’s Slippers, which I was told grow in The Dakotas in the heartland of America (2). However, in case any one should visit this post who has never attended to Botany, it may be convenient to explain the meaning of the terms used. We shall look at flower parts for which Orchids are distinctive, in comparison with common flowers. It may be helpful to follow the illustration immediately below (not mine; provided by Ms. Plantsandrocks).

A typical orchid flower (Sereno Aceto).

In common flowers, the stamens (male organs) surround one or more female organs, called pistils. In contrast, almost all Orchids have only one stamen, which is confluent with the pistil forming what we call the Column. As in common flowers, the Orchid stamen has an anther which carries pollen—the male vivifying element. However, in contrast with the pollen of common flowers, which consists of fine granular powder, in most Orchids the grains cohere in waxy masses called Pollinia.

Regarding the female organs, most Orchids have three united pistils. The upper part of the pistil is soft and viscid; this is the stigma. During the act of fertilisation the stigma is penetrated by long tubes emitted by the pollen grains; these carry the contents to the ovules (young seeds). However, the stigma of the uppermost of the three pistils has been modified into an extraordinary organ, called the Rostellum to which the Pollinia are attached! The Pollinia along with part of the Rostellum are removed by insects, and perhaps transported to another plant of the same species.

I will describe only briefly the outer divisions of the Orchid flower. The three outermost are the Sepals, generally coloured like the three inner ones, the Petals. The lowest Petal is larger, and often assumes a most singular shape; it is called the lower lip, or Labellum. It secretes nectar, thereby attracting insects.

The Labellum forms the slipper of the Greater Yellow Lady’s Slipper (MWI).

Now we shall discuss the genus Cypripedium, the principle object of this article. It is quite unusual, differing from other Orchids far more than any other two do from each other. An enormous amount of extinction must have swept away a multitude of intermediate forms, and left this single genus as a record of a former and more simple state of the great Orchidean Order. So let us look closely at the Lady’s Slipper, perhaps one of the most primitive of today’s Orchids.

Cypripedium pubescens; Catesby 1754, The natural history of Carolina, Florida ... (source).

Species in the genus Cypripedium possess no rostellum, and all three stigmas are fully developed and fully united (s. in illustration below). The single anther characteristic of all other Orchids is here rudimentary (a.), while the two anthers reduced in other Orchids are here fertile (a’.). Finally, the pollen-grains are glutinous and not united into waxy masses. There are other fascinating differences, but these are too minute and complex for anyone who has not a strong taste for Natural History. If you would like to know more, please refer to my book, starting on page 270.

Cypripedium, upper part of Labellum removed. I am much indebted to Mr. G.B. Sowerby for the pains which he has taken in making the Diagrams in my book as intelligible as possible.

We arrive at last at fertilisation and the role of insects, a subject to which I have devoted much time and thought. But first I shall explain the context in which I struggled—likely it will strike you modern thinkers as preposterous. In my time it was widely assumed that most flowers, being hermaphroditic (having both male and female parts), were self-fertilising. Even more shocking, it was only during the early years of my century that the idea of sex in plants finally emerged from the mists of profitless discussion and feeble experiment (3).

From Die Alpenpflanzen nach der Natur gemalt, F. Tempsky,1879-1884 (source).

At first glance the Lady Slipper appears to present an obstacle to fertilization by insects. As you can see in the illustration above, its broad Labellum is folded so as to form a sort of shoe, the end closed to any entry. However, close examination reveals two narrow slits through which an insect can reach with its proboscis the nectar waiting at the bottom of the Labellum. Most importantly, it can only do this by brushing against the two fertile anthers, thereby smearing its proboscis with the glutinous pollen. 

I tested this myself, by inserting a bristle which became smeared with pollen. We thus see how important, or rather how necessary for the fertilisation of the plant, is the curious slipper-like shape of the Labellum, in leading insects to insert their probosces by the lateral passages close to the anthers. The efficacy shown by nature is truly striking.

To those of you who have stayed with me to the end of this article, I am immensely grateful. More than a century has passed since I last spoke of Orchids and fertilisation with fellow naturalists on Earth, or so I was told (I have no sense of time passing). It is my sincere hope that you encounter this beautiful flower in its natural setting, and that you look closely and take the time to appreciate the cleverness of Evolution’s hand (4).

Charles Darwin, M.A., F.R.S., &c.

Greater Yellow Lady's Slipper in the wilds of Minnesota (MWI).

Notes

(1) This article was edited for greater concision and clarity, but without altering style or content. However, do NOT use it to quote Mr. Darwin. Instead use the Sources listed below.

(2) The yellow-flowered Lady’s Slipper in South Dakota is Cypripedium parviflorum var. pubescens. Its synonymy is lengthy: C. pubescens, C. flavescens, C. calceolus, C. calceolus var. pubescens, C. parviflorum var. planipetalum, and C. veganum. Our white-flowered species are C. candidum and C. montanum.

(3) This was explained by the author’s son, Francis, in his introduction to Chapter VII, "Fertilisation of Flowers" in The Life and Letters of Charles Darwin. See page 257.

(4) In South Dakota, Cypripedium parviflorum var. pubescens, the Greater Yellow Lady’s Slipper, has been found in wet meadows in the far eastern part of the state.

Sources

Barlow, Nora (Darwin's granddaughter), editor. 1958. The Autobiography of Charles Darwin, the first complete version. Darwin online

Darwin, Charles. 1862. Fertilisation of Orchids. On The Various Contrivances By Which British And Foreign Orchids Are Fertilised By Insects, And On The Good Effects Of Intercrossing. Darwin Online

Darwin, Francis, ed. 1887. The Life and Letters of Charles Darwin, including an autobiographical chapter. Volume 3. Darwin Online

Mapping Lake Lahontan—with contour lines & color

Landscapes past and present emerge from a surveyor's lines, as if by magic.

In 1881, Israel Cook Russell set out to map a lake that had been gone for 10,000 years, one that had filled the dry basins of northwest Nevada with fresh water. He was eager to survey the great lake, to study its features and learn about its life from beginning to end. And the timing was good! In line with practices of the day, the lake’s story would be told in maps that were artistic as well as utilitarian. 

Russell and several assistants spent three field seasons criss-crossing the immense basin of Lake Lahontan (1). They traversed “broad silent plains of desolation” and rugged mountains “unclothed by vegetation”, often in brutal conditions—hot, dry, no shade to be had. Yet they spared no effort. They surveyed basins past and present, sketching and describing sediments, gravel bars and relic shorelines. All was done in meticulous detail and with great precision (DRHMC).

Rarely did vegetation interfere with line of sight in surveys (ancient Lake Lahontan, now Carson Desert).

"section of Lahontan sediments”; note detail, precision typical of late 19th century scientific illustrations.

Fieldwork ended in the fall of 1883, with a visit by Russell to the far west part of the Lahontan Basin. Just two years later, Geological History of Lake Lahontan: a Quaternary lake of northwestern Nevada (Monograph XI) was issued by the US Government Printing Office (2).

At that time, distribution of GPO publications was governed by law (source). Members of Congress each received a set number, for constituents and institutions in their district. A separate run was ordered by the source of the document, in this case the USGS, to share with colleagues, scientists, other programs and institutions, and international exchange partners.

Surplus copies often were available for purchase, probably at cost-recovery prices (3). I bought a first-edition copy of Monograph XI, issued in 1885, from a rare book dealer for $40—not exactly a cost-recovery price, but reasonable (4). 

When Monograph XI arrived, I was astonished! It measures 9 × 12 inches, weighs 3 pounds 14 ounces, and includes 302 pages of front matter and text with 35 figures, all printed on smooth high-quality wove paper. Forty-five plates on heavier stock, each protected by interleaving tissue, are spread through the book, including 19 maps.

Plate XXXVII: Imitative Tufa forms.

Plate XLVI (excerpt) showing mountains, basins, playas, and an ancient lake.

While Russell and his crew measured, mapped, noted and sketched, chief geographer Henry Gannett was setting up the Survey’s Topographic Branch, including standards and practices for mapping. There were choices to be made, for example between easy-to-interpret hachures and information-rich contour lines.

In the late 1800s cartographers were still debating how to show topography, the shape of the Earth’s surface. What was the best way to create three dimensions on a flat sheet of paper? Europeans generally followed the longstanding tradition of using hachures—short parallel lines, a form of shading. Denser steeper lines were darker, indicating steeper slopes. Map readers found these "terrestrial maps" intuitive. Hachures were considered natural symbols for representing mountains, their locations, and their sinuousities.

Clarence King’s Topographical Map of Central California Together With a Part of Nevada (1873), in hachures.

Hachured mountains from King’s 1873 map; lake upper right is marked with waterlines—parallel lines decreasing in density away from shore.

However, hachured maps lacked precision and even basic information. While they showed location and shape of mountains ranges, distances and especially elevations were little more than suggestions. “They give us only a mutilated image of the land” (source).

Fortunately there was an alternative—contour lines, which connect points of equal elevation. Like hachures they show shape and slope, but with much greater precision.

Where contour lines are closer together, the slope is steeper (USGS 1897, from source).

Contour lines had been around since sometime in the 1700s, but were slow to be widely adopted. Many map users found them confusing. British soldiers are said to have objected, complaining that the lines were difficult to read while hachures were intuitive. Indeed, contour lines are abstract compared to hachures, requiring a greater cognitive leap. But with proper survey, they can provide a wealth of accurate information. 

For Gannett, the decision was easy: the USGS would use contour lines. To assist with transitioning from hachures, early maps often included shaded relief (aka hill shading).

Contour lines with shaded relief (sunlight always comes from the northwest).

Gannett also was forward-thinking with regards to map quality. USGS maps would be printed using lithographic stones, multiple colors, and one of the best color lithography firms in the US.

At that time, most maps were printed directly from metal plates, usually copper. Following the surveyor’s sketched map and data, a skilled engraver cut lines and points into a plate. Copper is suitable for engraving, being relatively soft, but for the same reason, engraved plates became worn with use.

“With great precision, an engraver carefully cuts away small ribbons of copper" (USGS).

“Tools of the trade ... the burin and the hand lens, resting on a contours engraving” (USGS).

The USGS did use copper plates, but NOT to print maps directly. Instead, the engraving was transferred from the plate to a much more durable lithographic stone. The process was complex. Below are step-by-step instructions, in brief (more information here):

• From a surveyor’s sketched map and data, engrave a copper plate.

• Ink the plate and lay a paper sheet on it.

• Press.

• Check print for errors, fix copper plate, make another print, continue until satisfactory.

• Transfer printed map image to lithographic stone using grease pencils, gum arabic and nitric acid (!).

• Ink the stone and lay a paper sheet on it.

• Press.

• Remove paper sheet from plate. Voilá—a map!

Repeat the last three steps for as many copies as are needed UNLESS ... the map has multiple colors. Then one must print EACH map with multiple stones, one per color!

A map "typically required 3 individual lithographic stones for printing, one for each color” (USGS). When the map was moved to the next stone, alignment was critical.

Colors typically used for USGS maps were brown (contour lines and shading), blue (water features) and black (cultural features such as towns and railroads). We see this in Russell’s maps, but with one obvious difference. Two shades of blue were needed, to distinguish lakes past and present.

Today’s small scattered lakes are pale blue; ancient Lake Lahontan is darker; darkest areas are playas (from Plate XLVI).

This complicated process of color printing could not be done in house. Instead, the government contracted with specialists, often Julius Bien & Company. Bien was a pioneer in chromolithography, and his scientific approach to printing made his products exceptional (5). Bien & Company produced many maps for the US government—for Pacific Railroad Surveys, the census, coast surveys, the topographic surveys of the USGS and more.

All color maps in Monograph XI bear the imprint "Julius Bien & Co. Lith."

The more I looked Russell’s monograph and maps, and the more I learned about the cartography and printing involved, the more I wondered … How did a costly science project like this get funded by the federal government, especially during the Gilded Age—a time better known for concentrated wealth, widespread poverty and government corruption.

It was funded thanks to John Wesley Powell, famous for his descent of the Colorado River through the Grand Canyon. He spent his later life in Washington, DC, much of it as Director of the US Geological Survey. Powell knew how to make things happen. He knew the right people, and how to lobby effectively. He even knew the best brand of cigars to hand out as gifts (Worster 2002). And in his requests for funding, he wisely slipped scientific studies—Ice Age lakes and such—in with mandated economic geology projects, chiefly surveys of mining districts. We who love the natural history of the American West are so grateful!

Our hero, with headman Tau-gu, c. 1873 (NPS).

Notes

(1) Russell’s first field season was a solo reconnaissance. During the next two he was assisted at various times by cartographers AL Webster and WD Johnson, and geologists WJ McGee and GM Wright. For more, see "Back to Lake Lahontan ..."

(2) The Government Printing Office is now "Government Publishing Office". 

(3) Sales were overseen by the Superintendent of Documents starting in 1895.

(4) I think I know the reason for the reasonable price. Plate XLVI, said to inhabit the Map Pocket, is missing. In fact, the map pocket on the inside back cover is pristine—perfectly flat and tight, never been used. And at 20 × 32 inches, the map wouldn't fit in that pocket no matter how it was folded. So I downloaded a file from the Rumsey collection and had it printed at the UPS Store.

(5) Julius Bien was a German-Jewish immigrant who fled the failed 1848 revolution. He went on to build one of the preeminent lithography firms in the United States. See Julius Bien, Master Printer and Cartographer for more about this man and his maps.

Sources (in addition to links in post)

Churchill, C. 2025. Variety in hachure. Carl Churchill Blog.

David Rumsey Historical Map Collection (DRHMC). Plate XLVI: Lake Lahontan : a quaternary lake of northwestern Nevada; Media Information. Accessed September 2026. [Many maps in this post are from the wonderful Rumsey collection.]

Edney, M. 2018. USGS printing techniques. Mapping as Process (blog).

Hacker, C. Depicting the Landscape - Part 2. in Cartographic Symbologies, The Art and Design of Expression in Historic Maps. Stanford University Libraries. Accessed September 2026.

NVG. Historical Printing Techniques, Intaglio, in Women’s Work. The Linda Hall. Accessed September 2026.

Raines, A. 2024. Fabricating the World: Copperplate Printing, in WORLDS REVEALED, Geography & Maps at the Library of Congress.

Russell, IC. 1885. Geological history of Lake Lahontan. USGS Monograph 11.

Worster, D. 2002. A River Running West, the life of John Wesley Powell. Oxford University Press.