Tuesday, November 29, 2011

Rescuing Rarities: Lilium iridollae

Lilium iridollae is an almost mythical plant; it was described in detail by it's discoverer, Mary Gibson Henry, and since that time, few studies have attempted to study this intriguing species in greater detail.  Known in the vernacular as the Panhandle or Pot of Gold lily, this species inhabits a few of the westernmost Florida panhandle and adjacent Alabama counties.  The plant grows in saturated, sandy soils that are not typically conducive to lily cultivation; frequent companions are Sarracenia spp., Drosera spp. Eriocaulon spp., Polygala spp., and Magnolia virginiana amongst many others.  Like some of these associated species, Lilium iridollae has become increasingly rare due to habitat destruction and fire suppression.

I was initially attracted to this lily by it's rarity, reputedly hard-to-grow nature, and potential as an exceedingly attractive conservation subject.  I made some enquiries to governmental institutions, and with their help was able to obtain a quantity of wild collected seed from an undisclosed location in Florida.  This seed was used to set up a germination and plant cultivation experiment.  Information from such experiments can be used to propagate plants for re-introduction into the wild on conservation sites and to produce nursery propagated plants to fulfill public demand.

Most of what is reported about seed germination is anecdotal and this species is considered difficult to grow in garden settings, although Mary Henry was able to grow it from seed to flower in 5 years in her Pennsylvania garden.  The goals of this study are to elucidate an efficient germination protocol, and to determine optimum conditions for sustained growth in cultivation.

A simple seed germination experiment was installed.  Seeds were sown on slightly moist perlite
and subjected to one of three temperature treatments: 70F in light for 5 days followed by incubation in darkness at 70F for 5 months, 70F in light for 5 days followed by cold stratification, and an "outdoor treatment" (seeds sown in 50/50 silica sand/peat medium and placed in a moderately heated playhouse).  Excellent information on lily species germination can be found on the Pacific Bulb Society website:


Lilium iridollae seeds sown on perlite in plastic bags.  The moisture level is critical and seeds/seedlings should be kept barely damp.  Seeds at the sides of the bag appeared to benefit from extra moisture and produced the best seedlings.

A L. iridollae seedling 2.5 months after being sown on perlite and incubated for 5 days in light and the rest of the time in darkness at 70F.  As suggested in the literature, the germination pattern of this species in delayed hypogeal, and the highest rate of germination and most vigorous seedlings were produced from seeds started at 70F.  Seeds sown on perlite and cold stratified for three months germinated only after transfer to 70F conditions, but seedlings germinated irregularly and were not as vigorous as seed incubated on perlite at 70F.

From left to right, L. michiganense, L. superbum, L. canadense var. coccineum, and L. iridollae (note the long roots of L. iridollae) after three months of growth in the greenhouse.

To compare development among species, I also sowed seeds of L. canadense var. coccineum, L. canadense var. flavum, L. michiganense, and two accessions of L. superbum.  L. iridollae germinated and developed more slowly than all other species.  Although four months at 70F is the general recommendation before switching the plants to cold stratification, I kept the L. iridollae at 70F for an extra months (5 total months) and the seedlings continued to develop.  After this they were transferred to 40F for three months.

On July 1, the seedlings were transferred to a 50:50 silica sand/sphagnum peat medium and irrigated with  reverse osmosis water.  Since it was quite hot at this time, the seedlings emerged immediately, grew throughout the summer and autumn, and are showing the first signs of dormancy as of this writing on November 29, 2011.  We have about 200 seedlings at this stage.

Seedlings are now quite robust and are being separated from community pots to maximize growth next season.  Progress of this work will be updated on this blog.

Lilium iridollae seedlings.  Photo taken on November 28, 2011.  Roots are 15-20 cm long!

Now, if I could only convince some kind soul to send me some seeds/plants of Lilium grayi and Lilium catesbaei.......

Sunday, November 27, 2011

Year of the Clematis

This past year I was fortunate to be able to travel widely in the U.S. for strictly botanical purposes.  While the primary intention of these travels was to search out an study Phlox, there were many other botanically interesting and ornamental plants that were incidentally encountered along the way.  One genus of plants that was a frequent and exciting surprise was Clematis.  It all started on the Edwards plateau of Texas...

As we traversed the rugged terrain of Lost Maples Natural Area, we caught our first glimpse of Clematis texensis peaking out from the base of limestone outcropping.

As we moved deeper into the canyon, we found C. texensis growing in boulder bars and scrambling over stunted shrubs.  These plants were larger and more floriferous than the plants growing in shade.

The brilliant red flowers set this species apart from other Clematis, and have tremendous ornamental value.  While there were no seeds ripe at the time, we serendipitously found a local native plant nursery (Natives of Texas Nursery, http://www.nativesoftexas.com/) who was offering seedlings for sale.  For those interested in the native plants of Edwards Plateau, I highly recommend this nursery.  I was also able to acquire plants of Penstemon triflorus and Phlox villosissima (Phlox pilosa ssp. latisepala).

Clematis texensis in cultivation.

Sometime later during the dog days of late July, I was botanizing in southwestern Kentucky.  While looking for the exceedingly rare Phlox pilosa ssp. deamii, we came across the demure Clematis versicolor.

The two-tone flowers of this species are less flamboyantly colored than C. texensis, but possess a demure charm unique to North American Clematis species.  Fortunately we were able to collect some ripe seeds of this rarely grown plant.

The abaxial leaf surface (underside) of Clematis versicolor

As of this weren't enough, an early autumn jaunt to heights of Dolly Sods revealed a single, very large plant of Clematis occidentalis var. occidentalis growing amongst boulders.

This species was scrambling along the ground, not climbing and of the stunted trees in the area.  There were no flowers to be seen, but there was a surfeit of seed, and we were able to collect a pinch.

A slightly different perspective showing Clematis occidentalis ssp. occidentalis near Dolly Sods.

On the same trip we also witnessed two Clematis species endemic to the shale barrens of West Virginia and Virginia.  These shrubby species are quite rare in the wild and even more rare in cultivation.

This is not the greatest photo, but in the lower right corner is growing what appears to be Clematis albicoma or C. coactilis.  This clematis was growing in the heavy shade of stunted Pinus virginiana; the seed had already dehisced.

A second Clematis (C albicoma or C. coactilis) grew in more exposed situations in full sun.  These plants had more stems and were covered with ripe seed.  

We collected a small portion of seeds and some of them have already germinated.

On a somewhat related note, it is hard to ignore the pronunciation of the word "Clematis", which is frequently the fodder of conversation.  Whenever I am asked to weigh in on the subject, I say this, " because its grows upon a lattice, some people call it Clematis, but Mr. Webster won't cease to his until you call its Clematis."

Wednesday, November 16, 2011

The Hydrangea Orchid: Cynorkis purpurascens or C. uncinata or C. calanthoides

This orchid seems to be suffering from taxonomic woes at the current time, and while I can't be exactly sure of the scientific name (purchased from Andy's Orchids as C. purpurascens or C uncinata, they also appeared unsure of the exact identity), I have coined a novel common name which I like quite well.

The Hydrangea orchid, yes, how fitting.  And here's why, each year this rarely grown terrestrial orchid emerges from dormancy and undergoes a miraculous transformation that attracts droves of  attention (well it would if on display at a public garden).  Putting to shame those orchids that require close inspection in order to be appreciated, this stunning species puts on a riotous hydrangea-esque floral display over a lengthy 4-month period, lasting from summer into late autumn .  The plants goes dormant in late winter and as temperatures rise and the day length increases, it begins to produce fleshy, bright green tongue-like leaves that continue to grow.  As the leaves expand in size the plant slowly comes into flower, and at first it may seem a somewhat disappointing (or, in the words of my friend Russell, "You lied to me, because I really thought that plant was going to be better."),  but as the summer progresses each inflorescence on a large plant will develop into a 20 cm diameter globe studded dozens of 1 inch diameter lavender purple flowers.   At peak flowering, the leaves are fully expanded and can be as much as 60 cm in length, providing the perfect foil for the floral display.

Another curious feature of this plant is the blue pollinium.  Cynorkis purpurascens is native to a large portion of the southern hemisphere.  This plant will seed seed when hand-pollinated and appears to tolerate self-pollination.  I have not looked at the seed under a microscope to assess the viability or sown any as one plant is quite enough. 

Cynorkis purpurascens is native to a Madagascar, South Africa, and some of the surrounding islands.  Like other orchids, this species appears to be quite morphologically variable (hence taxonomic confusion).

This plant is eay to grow.  It prefers hot, humid conditions in summer under partial shade with ample moieture.  As the days begin to shorten, the flowering comes to an end and growth ceases.  In mid-widwinter I stop watering the altogether.  The plant goes completely dormant, emerging only after temperatues and day-lengths increase in spring.  

Friday, November 11, 2011

Winter Flowering South African Bulbs

I 'm a huge fan of the South African flora.  It's hard not to be.  Some of the world's most beloved horticultural subjects have come from here, but this biodiversity hotspot has a seemingly endless supply of choice horticultural subjects still left to offer.  At the encouragement and generosity of a friend, I ventured into the world of the winter-growing growing neophytes, with a focus on the Iridaceae.  My collection has continued to expand.

The South African equivalent of Hyacinth, Lachenalia is a speciose genus displaying one of the widest flower color spectrums of any genus of flowering plants on earth;  Lachenalia viridiflora is one of the best of all.  It's easy to see why.  The sky blue flowers, with hint of aquamarine, surely stand as one of the most unique organisms yet to come from the angiosperm lineage.  This flower color is particularly hard to capture with a camera, but the following image is pretty close to a real-life glimpse.

The opulent Lachenalia viridiflora

Perhaps the most stunning plant in this collection in Lapeirousia oreogena

Another view of Lapeirousia oreogena; it's dwarf habit is retained in cultivation, making it exceptionally choice

This is a Haemanthus albiflos x Haemanthus spp. hybrid that was developed by a friend in Akron, OH.  These plants are flowering for the first time this year.  Attempts at producing an F2 generation failed as self-pollination was not successful.  I could not cross pollinate my two plants because the flowers on the plant shown failed to open properly.  No matter though, as the foliage is the  main attraction of this plant.

The showy bracts of the Haemanthus hybrid inflorescence that failed to open.

One of the best things about these winter flowering bulbs is that, if enough diversity is represented in a given collection, the flowers last from October until May.  More to come...