Passage for a Fern

By the time Captain Charles Mallard reached Hobart in November 1833, the grasses were trying to outgrow their accommodation. Two boxes of ferns, mosses and other plants had travelled on the raised deck at the stern of his ship. Apart from two or three ferns that appeared to have faded, he reported, everything was alive and vigorous. The grasses had been “attempting to push the top of the box off”.

Mallard had watered them once, with a light sprinkling during the equatorial heat. That was the whole water bill for the passage so far.

The boxes belonged to an experiment devised by Nathaniel Bagshaw Ward, a London doctor and naturalist. Mallard was carrying them aboard the Persian towards Sydney, testing whether plants could endure an ocean voyage inside a small enclosure of wood and glass. The outward journey had produced a promising result. Australian plants would make the return journey, and the cases would have to work through cold as well as heat.

A garden that would not grow

Ward had come to this problem from a much shorter distance. He wanted ferns to grow behind his London house. He made rockwork, arranged trickling water and planted mosses, primroses, wood-sorrel and woodland ferns. The garden failed. Ward blamed the smoke pouring from the surrounding manufactories.

In the summer of 1829, he put a moth chrysalisChrysalis×The protected stage in which a caterpillar changes into an adult butterfly or moth; the word can also mean its hard outer covering.Merriam-Webster · chrysalis ↗ into moist soil inside a wide-mouthed bottle. While watching for the insect, he noticed a fern and a grass appearing on the surface. Water evaporated as the bottle warmed, condensed on the glass and returned to the soil. The seedlings had acquired a more dependable water supply than his carefully arranged garden.

Ward moved the bottle outside a north-facing study window and kept watching.

In a letter read to the Linnean Society in June 1833, he reported that the plants had lived for more than three years without a drop of added water. He had also tried the method with more than thirty kinds of fern. The bottle's tin lid fitted loosely enough to permit some exchange of air.

The experiment eventually failed when the lid rusted and rain entered. Too much water killed plants that had survived so long without watering. It was an early indication of a problem that would follow the invention to sea: enclosing moisture was useful only while the roots could tolerate the amount enclosed.

Ward did not have an uncontested claim to being the first person to grow plants in glass vessels. Others had experimented independently. What he pursued with particular effect was a programme of trials, demonstrations and correspondence, followed by a practical test over an immense distance. Mallard's report supplied something a successful bottle on a windowsill could not.

Keeping the water, admitting the light

The travelling case enlarged the principle of the bottle into working cargo. Its wooden base held a bed of soil. A glazed upper structure admitted light and reduced the loss of moisture to passing air. Water leaving the soil and leaves could condense on the glazing and return. The case also intercepted salt spray before it reached the foliage.

This reduced the demand on a ship's fresh water and made plants much less vulnerable to an inattentive watering routine. It did not remove the need for judgment. A case could retain too much moisture, lose its glass or become dangerously hot in the sun.

Joseph Dalton Hooker left a particularly clear account of the work before departure. In New Zealand in 1841, the young botanist packed a case more than four feet long with ferns and other plants for Kew. He put pieces of wood in the bottom, then sandy soil, followed by the local clayey soil mixed with decayed plant matter. He watered until water ran freely from the plug hole, let the surplus drain, closed the hole and fitted the covers.

The packing was only the first stage of the journey.

Hooker's case went aboard the Exporter bound for Sydney, where it would enter the onward shipping network. He complained about the freight charge. A box large enough to carry a small planted bed also occupied space for which someone had to pay.

The commercial nurseryman George Loddiges found another obstacle in the captain. Writing in 1842, after experience with more than five hundred cases, he explained that good results depended on keeping them in daylight and repairing broken glass promptly. Some captains promised deck space, then stowed the cases below as soon as they were out of sight. Plants arrived ruined in equipment that should have protected them.

Loddiges singled out Mallard for the care he took. The captain who had noticed the ambitions of Ward's grasses was the sort of person a nurseryman wanted between his plants and the ocean.

A closer look · 10:02 · English

Inside a travelling glasshouse

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Ferns coming home

For the return experiment, the cases were refilled in Sydney with Australian plants. They travelled back on deck through the southern cold and then the tropics. Ward's later account described snow at Cape Horn and intense heat farther north. The Persian reached the English Channel in November 1834.

Ward reported that the plants had received no water during the return passage. Among the arrivals was Gleichenia microphylla, a fern whose living fronds delighted Loddiges when he accompanied Ward aboard. Seed in the soil had also germinated during the voyage, producing healthy Callicoma plants. Some of the cargo had grown itself on the way.

There was a domestic future for the idea as well. Ornamental glass cases allowed people to grow ferns indoors, away from the polluted city air that had defeated Ward's garden. Their architecture could become elaborate enough to make the plants tenants of a small conservatory.

An indoor glass garden could become an elaborate piece of furniture.

Decorative cases shared a humidity-preserving principle with shipping boxes. A miniature Gothic landscape had a different purpose from a bed of roots secured against rough handling at sea.

The transport version remained rougher equipment. Its customers included botanical gardens and nurseries, but also governments seeking to establish commercially valuable crops in their colonies. Keeping a fern alive could enlarge a collection. Keeping a quinine-producing tree alive could help establish a plantation.

Green leaves, failing roots

Cinchona grew in South America; its bark supplied quinine, a treatment for malaria. In 1860, Clements Markham organised a British effort to transfer valuable kinds to India. The undertaking depended on botanical identification, local knowledge, mountain transport and gardeners able to establish the plants before shipping them. A case could protect a rooted plant at sea only after someone had found it and brought it to the coast.

Markham's account names the gardener John Weir, the collector Robert Cross and the botanist Richard Spruce. It also records South American workers, including Pablo Sevallos and four Indigenous men on one collecting expedition. Markham had persuaded a judge to order local officials to procure the men and two mules. Packers, tree climbers and muleteers supplied work that the celebrated box could not perform. At Islay, Peruvian customs officials contested the export of one shipment; Markham secured authorisation to proceed.

Fifteen cases from the Caravaya collecting region left Islay in June 1860. At Panama, 207 plants were putting out new shoots. They reached England in excellent condition and remained healthy as far as Alexandria. The route then carried them into the Red Sea's heat, followed by a week's delay at Bombay.

According to Markham, their roots rotted. The leaves still looked fresh when the plants reached the Nilgiri Hills in southern India. Gardeners took several hundred green cuttings, but those failed to root. The water-preserving glasshouse had provided no escape from excessive heat.

Cross's red-bark collection sailed from Guayaquil in January 1861. It too travelled through England, where six plants were retained at Kew as insurance and replaced with six from another cinchona species. This time the Red Sea crossing fell in a cooler season. Markham credited both the weather and the watchfulness of a skilled gardener: 463 red-bark plants and the six replacements reached the Nilgiri Hills in vigorous condition.

Seeds travelled separately and germinated in abundance. Markham wanted living plants because they gave the new plantations a head start, not because a glazed box was the only possible way to move cinchona. Kew also kept reserve material against further failures. The transfer was organised around several chances of success.

Passengers nobody ordered

The cases moved substantial beds of living soil. Along with the roots, they could carry seeds, eggs, worms, fungi and other organisms that had no place on the consignment list.

In the 1870s, a hammerhead flatworm found in a Kew hothouse became the basis for the name Bipalium kewense. The species had come from elsewhere, although the garden's international plant collection made its exact arrival difficult to trace. Researchers identify plant transport, probably including early Wardian cases, as a route by which these flatworms spread. That does not identify the particular box that brought Kew's specimen.

The soil could carry more than the roots it was packed to protect.

By 1924, the American plant pathologist Beverley Galloway was advising against Wardian cases except under special instructions, warning that they transported insects, nematodes and other pests. Preserving a parcel of living earth had become a reason to restrict its passage.

Plant quarantine made soil a liability. Faster transport also reduced the need for a heavy glazed environment capable of supporting plants for months. Air freight could carry suitable material much more quickly, while the old cases remained expensive to send by sea.

In 1962, Kew received its last recorded Wardian-case shipment, carrying ornamental plants from Fiji. By then, the sea passage was reserved for material that could not conveniently travel by air.