Ginkgo biloba; Rediscovered in Jungle Gardens


The Value of a Fallen Leaf–The Rediscovery of Ginkgo biloba in Jungle Gardens


On December 17, 2017, I walked along the edge of a forest in Jungle Gardens.  It was a path I had walked many times earlier that year, only this time a single fallen leaf caught my attention.  Its brilliant yellow color and familiar shape belonged to a tree I knew very well but had never seen in the gardens.  It was Ginkgo biloba, the maidenhair tree or Ginkgo tree.

I was so surprised to see this leaf that I continued searching the area. As I got closer to the edge of the woods, the number of Ginkgo leaves increased until the ground was covered with them.  But, where was the tree, and how could I have missed it previously?

The forest in this area is compose primarily of large bamboos, as well as Viburnum suspensum, Podocarpus macrophyllus (Japanese Yew) and Cinnamomum camphora (Camphor tree).  The dense growth of viburnum mixed with culms of bamboo created an impenetrable wall that concealed everything in the forest growing behind it.  I made my way into this tangled jungle of plants, and about 12 feet into the brush I came upon two very large, tall trees growing only a few feet apart. When I looked up into their canopy I immediately knew I had found the source of the Ginkgo leaves.  Both trunks were covered in large vines and completely obscured from visibilty.  I carefully studied the area where they were growing.  The  abundance of seedling Ginkgoes all about the forest floor near the trees indicated the two Ginkgoes were male and female.  A substantial planting of Aspidistra elatior, the Cast Iron plant, grew around the base of the Ginkgo trees, a clear indication of prior landscaping.  At one time the Ginkgo trees and the Aspidistra were at the forefront of the edge of the forest. Over many decades other more aggressive plants mentioned above engulfed the area and obscured the landscaping and the Ginkgo trees.

Over the weeks that followed I took it upon myself to cut back the forest.  I removed all of the weedy introduced plants that were in front of the trees, and the vines covering the trees.  Thus bringing the Ginkgoes and Cast Iron plants as they were meant to be.

Both trees are very tall, though one is considerably larger than the other.  The larger tree is 24 inches in diameter and the smaller 14 inches. While there bases are 5 feet apart, many of their limbs touch and coil around each other.

Spring came and the trees began to leaf out. With the aid of binoculars I was able to determine which tree was male and which female.  By mid-July I began finding freshly fallen Ginkgo seeds.  Generally Ginkgoes shed their seeds in Autumn. Perhaps their early release was due to the heavy rains experienced those weeks. The many seedlings growing around the adults are mostly 6-7 inches tall, although some are 12 or even 14 inches tall.

This fall and winter I plan to explore the wooded area behind the Ginkgo trees to see if perhaps older seedlings are present.

The Ginkgo trees of Jungle Gardens are once again easily seen, in full view in front of the forest as they were intended to be.

The Asian Bayberry – Nageia nagi




Nageia Nagi  (formerly Podocarpus nagi, Broadleaf Podocarpus)


One of the rarest and therefore most interesting trees in Jungle Gardens is Nageia nagi, the Asian Bayberry.  This tree is seldom seen in cultivation, though it grows exceptionally well throughout the southern United States.

Nageia belongs to the podocarp family, Podocarpaceae, and was previously called Podocarpus nagi,  It was recently separated from Podocarpus and other genera in the Podocarpaceae because of its broad, flat, subopposite leaves lacking a midrib.  The leaves superficially resemble those of the unrelated and more famous New Zealand Kauri conifer, or Agathis.  Nageia‘s very attractive evergreen foliage has distinctive, dichotomously branched leaf venation, a pattern seldom seen in woody plants. The trees are unisexual, producing either male or female flowers.

The most impressive Asian Bayberries in Jungle Gardens are those located at Willow Pond near Bird City.  Two mature trees are just above the stone walkway that leads from the observation tower of Bird City toward the nearby Giant Bamboo Grove.  An extremely large, presumably very old male tree is about 60 feet tall and 19.5 inches in diameter.  Nearby there is a much smaller female tree. The pronounced size and age difference between these two trees suggests that a larger female tree was likely present at one time but has since been lost.  The smaller female tree is probably an offspring.  Numerous young volunteer Nageia seedlings grow in the adjacent Giant Bamboo Grove.  The larger male tree has peculiar scaly bark that peels off in vertical strips.  The smaller female tree produces an abundance of large, grape-size seeds nearly every year.  In the autumn the outer covering of the seeds turns dark purple as they mature and later fall to the ground.

A second grove of Asian Bayberries is located directly across from the parking area of Sunken Garden.  I estimate there are as many as 60 or more Nageia trees at this location. With the exception of one larger specimen growing apart, the trees range in size from only 1-4 inches in diameter.  The sheer concentration of trees in such close proximity makes the grove virtually impenetrable.  The large number of similarly sized trees suggests that this grove might have arisen as either a dense planting of young plants or from sown seeds.  Many of these small trees are mature, as evidenced by numerous seedlings appearing every year around the grove.

These trees should be a the top of the list of plants to find when visiting Jungle Gardens.

Chinese Sweet Gum – Liquidambar formosana




Liquidambar formosana,  Asian Sweet Gum,   Formosa Gum

Liquidambar formosana, commonly known as the Chinese sweet gum or Formosan gum, is a tree native to Eastern Asia.  There are two very large examples of this species growing side by side in Jungle Gardens.  The tree’s distinctive leaves are three-lobed, unlike the five to seven lobed leaves of the North American species, L. styraciflua.  The foliage of L. formosana turns an attractive red and yellow in autumn.  In its native Eastern Asia, the leaves are used to feed silk worms, and the wood is highly prized for making tea chests.

The individual flowers of L. formosana are monoecious (unisexual), but both male and female flowers can be found on the same plant.  Male flowers are in long, pendant catkins, whereas female flowers form dense, spherical heads, known as ‘gum balls.’  The fruits are burr-like because of the persistent female floral structures known as ‘styles.’

Although Liquidambar formosana is uncommon in cultivation,  I have seen it growing at the New York Botanical Garden and similar gardens in the Eastern United States, so it has a wide range of growing zones.

The two trees in Jungle Gardens flower every year and produce many gum balls, but I have not observed any seedlings in their vicinity.  I estimate the trees to be in excess of 80 years old, they are 24.5 and 22.5 inches in diameter.

I will never underestimate the value of exploring for trees in fall months when most are in some stage of dropping their foliage.  On December 16,  2017, while exploring a wooded ravine near the Old Nursery in Jungle Gardens with tree expert Adam Black of Peckerwood Gardens in TX, we discovered two trees that initially we identified as L. formosana.  Both trees, one in the ravine bottom, the other on the crest of the ravine, are 5.25 inches in diameter, suggesting they are the same age.  We first observed fallen leaves.  Their bright yellow color and unmistakable three-lobed leaves left little to the imagination as to their identity.   Two days later I returned to collect some of these leaves to make a voucher specimen.  Both trees had lost most of their foliage; the few leaves that remained on the trees were so high up that none were within reach.  As I collected leaves from the ground below the tree I quickly noticed the variable number of lobes.  Many leaves had the standard three lobes, but some were asymmetrical with four lobes and others had five lobes.  My collection contained an assortment of leaves from each tree that had an inconsistent number of lobes.  I immediately became suspicious that these two trees were not L. formosana but more likely hybrids with our native Sweet Gum species.

Returning to Archives with the leaves, I photographed, pressed and dried them.  A few days later I emailed the photos to Richard Olsen of the US National Arboretum.  He immediately confirmed that the trees were hybrids between the two species.  He went on to say that such hybrids have been produced only under controlled conditions and were unknown to occur in natural wild populations.

The two hybrids are a considerable distance from one of the parents, L. formosana. The other parent, L. styraciflua, is abundant at this location. Since Liquidambar species are wind pollinated (anemophilous) trees, the great distance of the hybrids from the large Formosan Gums, would support the conclusion that the male parent was L. formosana and the female parent was native L. styraciflua.  Its more feasible for pollen grains to travel long distances than it would be for fruits and seeds.

I have repeatedly visited both hybrids all spring and summer, searching for any evidence of flowers.   As neither shows any evidence of having flowered and no fruit have been found, I suspect they may be sterile.

The two hybrid trees,  discovered by chance, were only noticed because of their bright yellow, fallen leaves. Now that I know the hybrid exists on Avery Island, I will continue to look for them, and I am optimistic that more will be discovered.


The Avery Fern – Pteris cretica var. albolineata



Pteris cretica  (Pteridaceae)  The Cretan Brake Fern, The Avery Fern

Pteris cretica, almost pantropical in distribution, is so common in cultivation and escapes so easily in warmer regions that its true native home remains uncertain, although it is thought to have originated on the island of Crete.  Some authorities have labeled it indigenous to tropical America, including several states in the Southeastern United States.

The earliest record for Pteris cretica in Louisiana is from Avery Island on October 18, 1910, by R. S. Cocks, a botany professor at Tulane University.  He visited the island three years later, in April 1913, and made a second collection of the fern, commenting on the label “Deep ravines, very abundant.”  1913 was long before the formation of Jungle Gardens and the beginning of the exotic plant collections, indicating that the fern was not introduced to Avery Island as part of horticultural expansion. This information supports John Small’s claim that Pteris cretica could be indigenous to Avery (and other parts of Louisiana) as well as Florida.

There are two varieties of Pteris cretica that occur in the wild in Florida and Louisiana. Both have been found on Avery Island and both have been referred to as the Avery fern.  Pteris cretica var cretica is represented by herbarium specimens from collections up until the 1960s (this is the only variety collected on Weeks Island), but Pteris cretica var. albolineata is the variety now found living on Avery.   P. cretica var cretica has all green foliage, whereas albolineata has a bright white stripe down the middle of each leaflet.  Prof.  Clair Brown of LSU visited Avery Island many times and wrote about these ferns in his 1942 publication; Ferns and Fern Allies of Louisiana.   He states:  “It has been known there for a long time as the Avery Fern. . .” He also mentions the albolineata variety as being  “cultivated in large quantities in Jungle Gardens.”  It would be expected that by this time, the albolineata variety was brought into cultivation there by McIlhenny. Unless there is another discovery of variety cretica, it appears that albolineata is the only variety that currently survives on Avery.

I began exploring the salt dome islands of Weeks and Avery in 1971.  Prof. W. D. Reese of USL took me to a location on Weeks Island where Pteris cretica had previously occurred in abundance.   We found but a single specimen on a ravine wall that once had a thriving colony of hundreds of plants.  The plant was in such poor condition, with only a single badly tattered frond, that I considered it unworthy of making a collection.  Little did I know that would be the only plant I would find for the next 45 years.   We noticed that the ravine sides were covered in tall, clumping grasses, which indicated that the forest canopy had been seriously disturbed, allowing excessive sunlight to reach the ravines, potentially drying them out and making it very unsuitable for the ferns to persist, much less thrive.

From the 1970s-present, I explored the myriad forested ravines on Avery Island at every opportunity.  During that time, I also made several return trips to Weeks Island, always in search of the Pteris fern.   Unfortunately, the data from the specimens of the early 1900s did not document locations accurately enough that one could revisit them.   Reese and Thieret in their Botanical Study of the Five Islands, completed in the mid 1960s, found Pteris cretica on Weeks, but not on Avery.  It seemed like the fern might have completely vanished from Avery Island.  I always held out hope, however, that I would rediscover it in the “next” ravine I explored.

On October 17, 2016, I was guiding a group of university botany students on an afternoon tour of Jungle Gardens.   As we ventured on the trail in the Palm Garden, much to my surprise, I caught sight of two young plants of the Avery fern growing among the roots of a large tree along the path.   I said nothing, maintaining my composure, but I was elated to finally rediscover this fern growing on Avery Island after all the many years I had searched for it.  The following day I returned to the spot to observe the two plants in detail.  Both were juvenile plants, indicating a recent dispersal, no doubt from older mature plants.  Immediately, I began searching the nearby ravines and gullies near this location.   To my disappointment, I was unable to locate any additional ferns.

One month later, on December 16, while exploring near Sunken Gardens with Dylan Derouen, we found a weedy, disturbed area with an abundance of fern species.  As we made our way up the hillside, we found two more plants of Pteris cretica.  These were very large plants growing about 10-12 feet apart.  One was at the base of the hill, the other, a much larger plant, was higher up on the slope.   Both had fully mature, fertile fronds.  I showed these plants to Bernard Patout.  A few days later, not far from that site but inside Sunken Gardens, Bernard found a single juvenile Pteris fern growing among the stone work of a retaining wall and called it to my attention.

A full year later, December 17, 2017, while exploring for seedlings of the newly discovered Gingko trees near Bird City, I discovered more Pteris ferns.  Several distinct clumps of mature plants were scattered along the banks of a shady, shallow ravine that lies behind the grove of Giant Timber Bamboo not far from the Gingko trees.

After so many decades of failed searches for the Avery Fern, it has been rediscovered, thriving on the island, though in smaller numbers than decades past. I am optimistic there are more Pteris cretica populations waiting to be found on Avery Island.


Daphniphyllum macropodum


Daphniphyllum macropodum  (Daphniphyllaceae)

The identity of the evergreen trees in a grove along a small portion of Holly Hedge Road in Jungle Gardens eluded inquisitive visitors for many years.  The grove consists of perhaps a dozen trees, several of which are quite tall, although their trunks are not particularly large.  Those who saw the trees thought the stiff, leathery evergreen foliage resembled members of  the Laurel family, or perhaps the Magnolia family or maybe even some relative of Rhododendron. No one, however, knew the true identity of these trees.

Most of these trees are hidden behind large hollies and generally not visible while driving the roadway.   A couple of trees occur on the banks of both sides of the road, but finding them is not easy because of the large hollies that abound.  Additionally, two trees are some distance from the grove. One very young tree, growing in a wooded area near the entrance to Holly Hedge Road, is likely the result of recent seed dispersal.  The other, found by Mike Richard, Sr., some years ago, is a tall, mature tree, located on the summit of a forested ravine near the Old Nursery and just below the Sunken Gardens. This single large tree could be the last survivor of a possible former planting or another seed-dispersed plant from the main grove.

In late winter and early spring, the foliage produces a very attractive flush of color.  The leaves, which are arranged in a tight whorl or spiral, give the tree a very colorful appearance. The petioles (the supporting stalk of a leaf) of each leaf at the tip of a branch are bright pinkish red.  This bright petiole color lasts for several weeks, but eventually, as the leaves mature and age, it fades to green.  It appears the color of new leaves may provide the primary ornamental value of the tree.

During the spring of 2017, my first full year in Jungle Gardens, I visited these trees regularly in anticipation of finding flowers. On March 3 when I visited the grove of trees they were flowering.  The flowers were most peculiar.  Emerging from the axils of the previous year’s growth, they resembled clusters of small berries radiating out from a central axis.  The flowers had no petals or sepals, consisting solely of reproductive structures.  All those I observed were all pollen producing male flowers.  I knew, however, that at least one female tree had to exist because of the abundance of seedlings volunteering below the adult trees.

Examining the trees on July 5, 2017, using binoculars, I located a single female tree with clusters of fruit high up in the canopy.  Dylan Derouen scaled the slender tree and collected a fruiting specimen.

Because of the unique nature of the flowers, the identification of the trees as Daphniphyllum macropodum was not difficult.  Daphniphyllym is a monotypic genus in the Family Daphniphyllaceae.  There are about 10 species in the genus consisting of small shrubs and trees found in China, Japan, and Korea.  Like all species in the genus, D. macropodum is dioecious, meaning male and female flowers are borne on separate plants.

Perhaps the most interesting discovery regarding these trees occurred after their identification.  One day in July 2017 I examined some of the many folders in Archives that may or may not contain information pertinent to Jungle Gardens.  Much to my delight, in the very first folder I selected and went through I found a letter and attached plant list from the Yokahama Nursery in Yokahama, Japan, dated November 24, 1919.  The letter, addressed to E. A. McIlhenny, discussed his purchase of seeds. There was a second page that served as an invoice or statement of purchase.   The very last entry on that second page was that of Daphniphyllum macropodum seeds he had purchased.

We now had a document in Archives with the plant’s name and the date of acquisition.   Ninety-nine years later, this species is still flourishing in Jungle Gardens.