Torreya Taxifolia

''Torreya taxifolia'', commonly known as Florida torreya or stinking-cedar, but also sometimes as Florida nutmeg or gopher wood, is an endangered subcanopy tree of the yew family, Taxaceae. It is native to only a small glacial refugium in the southeastern United States, at the state border region of northern Florida and southwestern Georgia.

Species discovery

In 1821 colonial control of the Florida Territory shifted from Spain to the United States. Plantation owners and their slaves began to move into the territory, exacerbating conflicts with the native peoples and the existing population of runaway slaves. One such plantation owner was the patriarch of the Croom family, who in 1826 purchased land around the town of Tallahassee. When he died in 1829, his two sons inherited and invested further in the region, buying up or leasing other plantations.

One of the two sons was Hardy Bryan Croom. Croom had studied law and became a state senator in North Carolina in his early thirties, but he also devoted time to exploring the sciences. Among other scientific interests, he described himself as fond of botany. He assembled a small personal herbarium and authored a monograph on the carnivorous plant genus ''Sarracenia''.

While exploring along the east side of the Apalachicola River, Croom noted that the flora was quite different from elsewhere in the Tallahassee region. Beginning in 1833 he sent dried specimens to herbaria in the north, including that of another glacial relict woody plant found in the same, limited area. That plant is now known as Florida yew, ''Taxus floridana'', and it is also critically endangered. In 1834 Croom initiated correspondence with the botanist John Torrey. Torrey carried forward studies of the species that would eventually carry his name after the tragic death at sea not only of Croom but also of his wife and children. Their shipwreck occurred during a hurricane in 1837, off the coast of North Carolina.

Taxonomy and naming

In 1838 this novel species was described by George Arnott Walker-Arnott from specimens sent to John Torrey and collected in Florida by Hardy Bryan Croom.

Arnott commemorated Torrey in the generic epithet. The etymology of the specific epithet is from Latin ''taxus'', meaning 'yew', and ''folium'', meaning 'leaf': i.e., 'yew-leaved'. Other species of ''Torreya'' have longer, less yew-like leaves, but this is not the reason that it was given this name, as the other species were described after this one.

The University of North Carolina Herbarium has a single specimen, originally from the Jesup Herbarium of Dartmouth College, sent by Croom in 1833 from the "Apalache River" (now, Apalachicola River). Curiously, it was first labelled as "''Taxus montana'' Willd.", a South American tree, which was then later changed to '' Podocarpus taxifolia'' from southern New Zealand, and finally relabelled as ''Torreya taxifolia''.

Taxonomic and naming changes also occurred when European botanists analyzed herbarium samples. The species was moved to the junior synonym ''Caryotaxus taxifolia'' in 1865 by Johann Baptist Henkel and Wilhelm Christian Hochstetter in their monograph on the conifers of the world, ''Synopsis der Nadelhölzer''. In 1873 Karl Heinrich Emil Koch moved the species to ''Foetataxus taxifolia''. In 1891 Edward Lee Greene validated Constantine Samuel Rafinesque-Schmaltz's generic epithet ''Tumion'' and erroneously moved this species there as ''Tumion taxifolium''.

In Thomas Nuttall's entry about ''Torreya taxifolia'' in his book about American trees, which was published in 1849 although it had been for the most part completed in 1841, he relates that in the correspondence Torrey had sent him, mention had been made of specimens of another species of taxoid tree which had been sent to him by Croom from the same region. To this plant Nuttall "doubtfully attaches the name" ''Taxus montana'', somewhat of a nomen nudum, because Nuttall never actually described the plant besides quoting a summary description from Torrey's letter to him. Nuttall is doubtful about the taxon, because according to him it seems "scarcely distinct" from ''T. brevifolia'' of the Pacific Northwest. Following the publication of this work, however, he was attributed as the author of this scientific name. By 1865 this name was misapplied to ''Torreya taxifolia'' under the name ''Torreya montana''. Henkel and Hochstetter synonymised this taxon with ''T. taxifolia'' in their work mentioned above. According to the Index Kewensis this was in error; the name ''Taxus montana'' had actually already been given to a species, now '' Prumnopitys montana'', described (validated, in fact) in 1806 by Carl Ludwig Willdenow from specimens collected by Alexander von Humboldt and Aimé Bonpland on their famous scientific exploration of the Americas, and Nuttall had in fact referred to Willdenow's species. John Nelson, in his more utilitarian as opposed to scientific 1866 horticultural handbook of firs and pines for growing in Britain, introduced the name ''Foetataxus montana'' to write about ''Torreya taxifolia'', apparently unaware of the German publication the previous year. In fact, all these sources were wrong, for Nuttall states that he found a newer specimen of Croom's, of the same taxon, in the Herbarium of the Academy of Natural Sciences of Philadelphia labelled as ''Taxus floridana''! Despite that the original synonymy with ''T. floridana'', all these names are still maintained in the synonymy of ''Torreya taxifolia'' in some modern databases as of 2020.

Type species of genus ''Torreya''

''Torreya taxifolia'' is the type species of the genus ''Torreya'', owing to the timing of its entering herbaria used in western science. The genus has far greater representation in east Asia and also in the mountains of California (''Torreya californica'') than in its relictual range in Florida.

Family level classification has been controversial, but with genetic analysis it is generally placed in the yew family, Taxaceae. Its closest relative within the yew family is genus ''Amentotaxus''.
Genus ''Cephalotaxus'' also used to be considered a close relative, but it is now classified within an entirely different family, Cupressaceae.

Vegetative structure among ''Torreya'' species is very similar, as seen in the image above. All samples were taken and photographed onsite at Cox Arboretum in Georgia (US). All were young saplings growing in similar light and soil conditions. Florida yew, ''Taxus floridana'', is easily distinguished from Florida torreya by touch: while both genera have pointed leaf tips, the yew tip is soft while torreya is so hardened it easily punctures skin.

Common names

The United States government official page listing the endangered status of ''Torreya taxifolia'' shows only one common name, Florida torreya. The current (2020) version of the official recovery plan for the species lists three common names, in order: Florida torreya, Florida nutmeg, and stinking cedar. The current (1993) page for this species of the U.S. Department of Agriculture Fire Effects Information System, lists six common names, in this order: Florida torreya, Florida nutmeg, gopherwood, polecat wood, Savin, stinking cedar.

Internationally, the common names listed for ''Torreya taxifolia'' are, in order, Florida Nutmeg Tree, Florida Torreya, Gopherwood, and Stinking Cedar. This is in accordance with the latest (2010) update of the species page of ''The IUCN Red List of Threatened Species''. The Integrated Taxonomic Information System lists two common names: Florida nutmeg and Florida torreya.

There is a long history of documented common names that are also paired with descriptions of the species features that may have given rise to such names. One of the first prominent botanists whose documentation of the species includes common names was Thomas Nuttall. Writing in the early 1840s, he proposed the name "yew-leaved torreya." He noted that locally the species was known as "stinking cedar." He ascribed this name to the "strong and peculiar odour" of the timber, especially when it is "bruised or burnt". He also mentioned that the seed, covered in an aril, is approximately the size of a nutmeg.

In 1865 the German botanists Johann Baptist Henkel and Wilhelm Christian Hochstetter noted that the Americans called the tree "stinking cedar" and "wild nutmeg". They explained that the name "nutmeg" is derived from the bone-hard shelled and acorn-sized seeds, which are covered in an aril somewhat similar to that of true nutmeg. They also described that when the leaves are crushed they exude a pungent and disagreeable odour, which is why the local Americans used the name "stinking cedar". They themselves called the plant "''Torrey's Nuss-Eibe''", which translates into English as "Torrey's nut-yew." According to the British gardening writer John Nelson in 1866, ''Torreya'' species in general were known as "stinking cedars" or "stinking nutmegs" by the locals. Recommending the name "mountain yew" for British use, Nelson was unaware that this Florida species grows almost at sea level — and thus nowhere near any mountains Of all species of its genus, Florida torreya is the only one whose historically native habitat is not in mountainous terrain.

In the spring of 1875, Harvard botanist Asa Gray embarked on a trip to the panhandle of Florida, to "make a pious pilgrimage to the secluded native haunts of that rarest of trees, the ''Torreya taxifolia''". The trees observed by Gray during that trip grew up to a meter in circumference and 20 meters tall. Pertaining to its common name, he wrote:

"The people of the district knew it by the name of 'Stinking Cedar' or 'Savine' — the unsavory adjective referring to a peculiar unpleasant smell which the wounded bark exhales. The timber is valued for fence-posts and the like, and is said to be as durable as red cedar. I may add that, in consequence of the stir we made about it, the people are learning to call it Torreya. They are proud of having a tree which, as they have rightly been told, grows nowhere else in the world."

Description

Technical description

''Torreya taxifolia'' is an evergreen tree that may reach heights of with an diameter trunk, although it typically grew to tall and in diameter, and most stands today are composed of immature trees of less than tall. see also
RangeMap
/ref> The crown is open and conical in overall shape, with whorled branches. These branches are spreading to slightly drooping. The bark of two-year-old branches are coloured yellowish-green, yellowish-brown or grey. On mature trees the bark is only about 0.5 inches (1.3 cm) thick and is irregularly divided by shallow fissures.

The stiff, needle-like leaves are sharp to the touch and are arranged in two ranks on the branches. Images on this page show their dimensions; sizes vary depending on access to sunlight and the tree's overall health. The leaves are glossy green above and light green below, with a very slightly sunken grayish stripe of stomata on either side of the midrib on the underside, and slightly round in transverse profile on the topside. The leaves have an unpleasant, strongly pungent, resinous odor when crushed.

Genus ''Torreya'' is subdioecious, with separate male and female plants that may however include branches bearing cones of the opposite sex. The male (pollen) cones resemble those of a common yew, but are much larger and have imbricated scales (bracts) at their base. They are 5–7 mm long, grouped in lines along the underside of a shoot. The female cones when young are more angular than the male (as seen in the photo to the right). They are grouped two to five together near the tip of a branchlet. Tiny at first, they mature in about 18 months to a drupe-like structure with the single large nut-like seed (photo at right) surrounded by a fleshy covering called an aril, long including aril, about the size of a nutmeg. The aril is green but becomes streaked with purple as it matures, advancing to orange or fully purple in late fall. Unlike true yews, in which the aril forms a "cup" around the seed, in this plant the aril completely encloses the seed, leaving only a minute perforation at the end. When the aril is removed, the seed bears a striking resemblance to a large acorn.

Subcanopy growth adaptations

Species within the ''Torreya'' genus are all adapted to establish and grow slowly as subcanopy woody plants in forest habitats of moderate to dense shade. In this way, their leaf structure and growth habit resemble species of yew, genus ''Taxus'', which is a close relative.

Stems will lean in very shady conditions, in quest of patches of sunlight. Extremely leaning stems within a shady subcanopy gather moss as they age. An old leaning stem that fails to access sunlight will perish, but not before the long-lived root crown has given rise to one or more younger stems searching for sunlight in different directions.

Basal sprouting new stems from the root crown is thus another vital adaptation for long-term persistence in a subcanopy ecological niche. Basal sprouting will occur if young seedlings are browsed by herbivores. It also occurs in saplings when a multi-stemmed growth form enables a wider quest for patches of sunlight. But even in healthy, mature trees, new basal growth is present as a hedge against damage to the main stem. (References in the image caption.)

Distribution

Wild population

''Torreya taxifolia'' is restricted to limestone bluffs and ravine in the central part of the northern Florida Panhandle and immediately adjacent southernmost Georgia. There used to be one small colony west of the Apalachicola at Dog Pond in Jackson County, but it no longer exists.

This endemic tree grows along the Apalachicola River just south of the confluence of the Chattahoochee River and the Flint River, which drain the southern Blue Ridge Mountains, a subrange of the Appalachian Mountains. It occurs only in the Florida counties of Gadsden and Liberty and extends one mile into Decatur County, Georgia. The area in which it naturally occurs is , stretching along the Apalachicola River.

Alvan Wentworth Chapman, a leading botanist of his time in the southeastern states, wrote in 1885 that "Florida torreya" was found only in "widely separated clumps or groves" and appeared to be "exclusively confined" to the cliffs along the east shore of the river and to "the precipitous sides of the ravines" that dissected those cliffs. "It is never seen in the low ground along the river, nor on the elevated plateau east of it, nor, indeed, on level ground anywhere."

Prehistoric distribution

''Torreya taxifolia'' is a member of an ancient genus at least 160 million years old. Fossil evidence indicates genus ''Torreya'' was widely distributed across the Northern Hemisphere beginning in the Jurassic period and as recently as the Pliocene

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