Hoya kerrii: The Roots He Couldn't Leave

Hoya kerrii: The Roots He Couldn't Leave - Gathering Moss

I have a variegated Hoya kerrii growing in my collection. It is a beautiful plant: thick, heart-shaped leaves with cream around their margins, green through their centers, and a vine that grows the way a Hoya is supposed to grow.

That probably is not how most people first meet it.

Most people encounter Hoya kerrii around Valentine's Day, when a single heart-shaped leaf appears in a tiny pot and gets sold as a living valentine. I have never liked those things. Taking one leaf from a beautiful climbing plant and marketing it as though it were the whole plant feels like a botanical version of spray-painting a cactus.

The complete plant is far more interesting. So is the person behind the second word on its label.

Kerrii exists because Kerr was a person.

The doctor who went to Siam

Arthur Francis George Kerr was born in Ireland in 1877. The son of a doctor, he studied medicine at Trinity College Dublin and followed his father into the profession. While he was there, however, another interest took hold.

One of Kerr's teachers was the botanist Henry Horatio Dixon. Kerr later credited Dixon with sparking his interest in botany and helping him obtain the medical position that took him to Siam, the country now called Thailand.

In 1901, at only 24 years old, Kerr left Ireland for the other side of the world. Medicine brought him to Siam, but plants increasingly shaped the life he built there.

He arrived in Bangkok that June and later worked as a medical officer in Chiang Mai. He became fascinated by the plants around him, especially orchids. He collected, drew, observed and recorded. After a visit to the Royal Botanic Gardens, Kew, in 1908, he began collecting the wider flora of Siam systematically.

That meant numbered specimens, preserved material and careful location records. The plants could be sent to botanical institutions, where specialists compared them with known species and determined whether they represented something science had not formally described.

Kerr left an enormous paper trail. The Library and Archives at Kew holds 28 diaries, photographs, correspondence, journey records and 158 plant-tag books. He recorded routes, elevations, bearings, markets, villages and the practical frustrations of travel. In one 1904 diary entry, the day begins before five in the morning with the discovery that six ponies have disappeared.

Details like that pull him out of the herbarium cabinet. He was a doctor in northern Siam, fascinated by plants, traveling through a country whose flora remained incompletely documented, occasionally wondering where the hell his ponies had gone.

Collection number 1810

By late April 1911, Kerr was collecting plants around Doi Suthep, the mountain above Chiang Mai. His numbered collections show that he was not searching for one special Hoya. He was documenting plants in sequence, including collection numbers 1806 through 1815.

One of those was number 1810.

The surviving type sheets at Kew and the Natural History Museum in London identify it as a Hoya collected on Doi Suthep. Their labels give the date as 29 April 1911. Craib's published description has been reported as giving the date as 2 May, although I have not yet been able to check that date directly against the original printed page.

That discrepancy made me wonder whether Kerr's diaries could tell us what happened. Did he immediately recognize that the plant was unusual? Did he write about where it was growing or what caught his attention? Was one of the dates simply copied incorrectly?

I contacted the Library and Archives at Kew. Griffin Royle, an Archives and Registry Graduate Trainee, searched Kerr's general diary and the more collection-oriented botanical diaries. He checked the relevant 1911 material and even searched April and May entries across nearby years in case something had been misplaced or misdated.

There was nothing to find.

Kerr was not keeping his general diary consistently during April and May 1911, and there are no entries for the days we need. The surviving collecting notebooks do not cover this particular journey. No known diary account of Kerr collecting Hoya kerrii survives.

That answer is disappointing, but it matters. It means we cannot honestly reconstruct Kerr's thoughts on the mountain. We cannot say he stopped in amazement, knew instantly that he had found something new, or understood that people would still be growing its descendants more than a century later.

What survives is less dramatic and more tangible: Doi Suthep, collection number 1810, a label dated 29 April 1911, a different date reported from the published description, and preserved pieces of the plant itself.

More than 115 years later, Kerr's specimens still exist. I can look at a dried plant he collected on a mountain in northern Siam and then walk over to a living plant in my Indiana collection carrying his name.

Kerr collected it. Craib named it.

Living material reached Europe and flowered in cultivation later in 1911. William Grant Craib, a Scottish botanist closely involved with plants arriving from Siam, formally described the species in the Bulletin of Miscellaneous Information, Kew that December.

He named it Hoya kerrii.

The division of credit is useful to understand. Arthur Kerr collected the plant. William Grant Craib formally described and published its name. That is why botanical references may place Craib's name after Hoya kerrii: Kerr is the person honored by the species name, while Craib is the botanist who published it.

Their working relationship stretched across thousands of miles. Kerr collected and documented plants in Siam. Craib studied material that arrived in Britain. Specimens and letters moved between the field and the herbarium, gradually contributing to a scientific record of Siam's flora.

Craib eventually honored Kerr in an even more unusual way. In 1927, he established a legume genus called Afgekia. Arthur Francis George Kerr. A. F. G. K. Afgekia.

The genus name is understood to be built from Kerr's initials, although I have not been able to examine Craib's original 1927 wording directly. It is such an odd and personal botanical name that it makes the professional relationship between them feel a little more human.

A life larger than one Hoya

If Kerr's story ended with collection 1810, we would miss almost everything important about him.

His collecting became more extensive and organized. By 1920, he was working officially in Siam's Botanical Section and later became Government Botanist. The doctor who had begun by collecting orchids had become a professional botanist engaged in the enormous task of documenting a country's plant life.

He did not do it alone.

Kerr's work depended on a much wider circle of collectors and collaborators. One of the earliest was Emily Collins, an Englishwoman living in Siam who became a serious botanical collector in her own right. Later, Thai collectors and assistants, including Nai Put and Nai Rabil Bunnag, worked within the botanical network around Kerr and helped carry the work forward.

Their names are much less familiar today. That is partly how botanical history was recorded: the name printed on a publication or attached to a species could overshadow the people who helped put the plant in front of science. The history becomes badly distorted when it is presented as one European botanist entering the jungle and discovering everything by himself.

Kerr was crucial to the effort, but he was part of a network.

That network fed into Florae Siamensis Enumeratio, an attempt to catalogue the plants of Siam. Craib began publishing the work in the 1920s, and Kerr later carried it forward. A modern Flora of Thailand project would begin decades afterward, and the work continues today. That persistence says something about the scale of the question Kerr and his colleagues were trying to answer: What grows in Thailand?

The family behind the records

Kerr's personal life also resists the simple picture of a solitary collector.

According to John Parnell's research into Kerr's life, Kerr married Daisy Muriel Judd in 1903, and they had four daughters: Eileen, Barbara, Ann and Kathleen. During the First World War, Kerr returned to medicine and served in the Royal Army Medical Corps. His family lived for a time in southern France while he served in France.

After the war, the family returned to Siam. Then Daisy died in Chiang Mai in October 1921, while still in her thirties. Her grave remains in the Chiang Mai Foreign Cemetery.

Kerr left Siam for England shortly afterward. His daughters remained there in the care of others when he returned to Siam in March 1922.

It would be easy to impose a modern judgment or invent an emotional explanation for that decision. The surviving evidence does not tell us enough about the family's arrangements, conversations or choices. What it does show is that Kerr's daughters remained connected to his story.

Decades later, when botanist M. Jacobs reconstructed Kerr's life, three of his surviving daughters helped. Eileen, Barbara and Ann supplied family material, connected Jacobs with people who had known their father and read his resulting account. Institutions preserved Kerr's papers, but his family also helped make it possible for later generations to know him.

Giving up the jungle

In January 1931, Kerr wrote from Bangkok to Henry Dixon, the teacher who had first encouraged his interest in botany and helped him reach Siam.

Nearly thirty years had passed. Kerr was no longer the young doctor Dixon had helped send overseas. He had practiced medicine, served in a world war, married, raised a family, lost his wife, explored Siam and spent decades collecting and documenting its flora.

He also knew that his time there was coming to an end.

“The jungle has great attractions for me,” he told Dixon.

He credited Dixon with both awakening his interest in botany and helping him obtain the job that had brought him to Siam. After three decades, Kerr still remembered who had opened the door.

Kerr returned to England in 1932. He worked at Kew with Craib on Florae Siamensis Enumeratio until Craib died the following year, then continued the work himself.

Even failing health did not end his observations. During 1940 and 1941, Kerr recorded seasonal events in nature for a Royal Meteorological Society program. As another world war unfolded, the British Air Ministry also took an interest in the maps he had made during his years in Siam.

Arthur Francis George Kerr died in Kent in January 1942. The fullest account of his life reports heart trouble complicated by asthma and bronchitis.

He had left Siam, but the country remained embedded in his work, his relationships and his family history. His wife was buried there. His colleagues were there. Tens of thousands of plant collections connected his name to its landscapes. In his own words, he did not know how he would feel about giving up the jungle altogether.

That is why Hoya kerrii feels like more than an honorific on a plant label.

The Hoya is one surviving root of a life Kerr could leave geographically but never entirely leave behind.

Sources and further reading

This article accompanies Episode 3 of Names Have Roots, “Hoya kerrii: The Roots He Couldn't Leave.”