[Trillium-l] Trillium erectum x flexipes

Mike Slater mslater at voicenet.com
Tue May 17 16:23:36 CEST 2011

The "Susquehanna Trilliums" of the flexipes x erectum types are extremely 
variable as Jim and John  said. Some of my pictures of them are on this page 
at the NARGS Wiki: Rock Garden Encyclopedia 
http://nargs.org/nargswiki/tiki-index.php?page=Susquehanna+Trilliums These 
are from Shenk's Ferry and Ferncliff Preserve both limestone glens along the 
Susquehanna River in Lancaster County Pennsylvania.  (of note: there is one 
other limestone Glen on Lancaster County side of the River and It has no 
Trillium of the Susquehanna type but it does have Trillium grandiflorum! 
This is the only extant site I know of for T. grandiflorum that may be 
natural/native in Southeastern/Southcentral Pennsylvania.)

As evidence of hybridization in the Trilliums at Shenk's Ferry Wildflower 
Preserve I have found a number of plants with flowers exhibiting the 
bullseye pattern of color the Fred and Roberta Case described in their book 
"Trilliums"  I have found Both the red centered and white centered 
individuals at shenk's Ferry. Unfortunately the best examples I photographs 
were lost when the film developer ruined 3 rolls of slide film by developing 
them as prints. (That was why I switched to digital!)

As for the rarity of red flowered plants at Shenk's Ferry My Friend Tim 
Draude, a botanist from Lancaster, has documented many instances of the red 
flowered plant being the ones that are poached from the wildflower preserve. 
Tim has showed me holes dug in the ground where red-flowered plants were 
growing a few days before! Since the reds are rare there they are most 
favored visitors with shovels. We are hoping now that the preserve is being 
transferred from the Electric Utility to the Lancaster County Conservancy 
protection will be improve for the wildflowers there.

At the NARGS Annual meeting in Pittsburgh a number of years ago I was in a 
field trip group that included Fred Case that went to Raccoon Creek State 
Park where we saw a population of similar Trilliums that Fred felt were most 
likely T. erectum x flexipes in origin.

I has personally speculated about another possibility of parentage for these 
trilliums.  There is typical Trillium erectum in Northern Lancaster County 
but no typical Trillium flexipes for many hundreds of miles that I know of, 
but there is another member of the "Erectum Group" which grows in the area 
and has white ovaries i.e. Trillium cernuum.

The evidence I have is my observation of an interesting group of plants on 
Long Island NY. In a small town Park on the North Shore I  observed a number 
of Typical T. erectums in bloom and also a good number of T. cernuum growing 
among them. The only atypical plant I saw looked like it could have been 
transplanted from Shenk's Ferry! Unfortunately I didn't have my camera with 
me so no pictures and I haven't been back there in Late April again.  I 
would like to try to recreate this cross in the garden but although Trillium 
cernuum grows naturally within five miles of my house I can't seem to get it 
to bloom in my garden. Next year I will have to ferry some pollen to my T. 
erectum plants and then wait. So stay tuned and I will report in 5 to 7 
years if I am successful.

Mike Slater

> Message: 3
> Date: Mon, 16 May 2011 16:56:21 -0400
> From: Jim McClements <jimmcclem at gmail.com>
> Subject: Re: [Trillium-l] Trillium erectum x flexipes
> The subject of Trillium hybrids, particularly in the "erectum complex",
> should certainly include consideration of what I often refer to as the
> "Susquehanna Trillium", found by the thousands in spectacular hillside
> masses at Shenk's Ferry PA, but also on both sides of the Susquehanna 
> River
> in the same general location. Most trillium addicts in my area (Pa, NJ, 
> and
> Del) are quite familiar with these.
> The best guess (by Dick Lighty, formerly at Mt.Cuba Gardens) about these 
> is
> that they probably represent a relict hybrid between white T. erectum and 
> T.
> flexipes. They are 99.99% white petalled, but with ovary color ranging 
> from
> white (like flexipes) to black (like erectum), and some variation in 
> shape.
> Aside from ovary color the plants are pretty much uniform. I have quite a
> few of these in my garden (grown from seed), where they are quite vigorous
> and show the same ovarian variations as the wild population.
> Could this be the source of the "erectum/flexipes hybrid" that started 
> this
> thread of discussion?
> Jim McClements
> Message: 4
> Date: Mon, 16 May 2011 23:00:39 -0400
> From: "Fern Hill" <fernhill at voicenet.com>
> Subject: Re: [Trillium-l] Trillium erectum x flexipes

> I think Jim has a good and valid point.  My late wife and I were Mt Cuba 
> Guides when Dick was director.  On one outting he took the guides to look 
> at the Susquehanna trillium from, as I recall, the Conowingo Dam in the 
> south to near Harrisburg in the North.  We visited a site near either 
> Conowingo or Holtswood dams where there was a sparce (due to restricted 
> habitat) trillium population on the west side of the river  At Shenk's 
> Ferry the big population is on the East side while across the river from 
> Shenk's Ferry at otter Creek there is a large population on the West.  The 
> North population South of Harrisburg was nearly extripated by someone 
> beginning a garden, but a few plants remained under brush piles in a small 
> ravine on the West side of the river just as its stream entered the river. 
> On other ocassions Janet and I were shown some trillium population NE of 
> harrisburg by friends.
> Dick's hypothesis is that the Shenk's Ferry population in particular was - 
> as Jim said - a relict population that resulted from hybridization of red 
> erectum with flexipes followed by back crossing with flexipes.  He 
> observed that North  (the Harrisburg) site had a high concentration of 
> pinkish and off-white plants while further North the trillium were all red 
> erectums.  My memory is that the Otter Creek population had somewhat 
> smaller flowers and looked more flexipesish than Shenk's Ferry and south. 
> I recall no colored forms South of Shenk's Ferry or at Otter Creek.  On 
> rare occasion Shenks Ferry produces a speckled pinkish form and the 
> ovaries vary as Jim indicated.
> There are some historical points that need to be considered before the 
> hybridization hypothesis is fully accepted.  At Shenk's ferry the 
> population is not entirely "natural"  The Glen there was the site of a lot 
> of industrial activity in the 1800's.  There was an active inn - probably 
> at the flat area at the base of the entry hill.  A rail road cut across 
> the glen about half way up and further up there is the foundation of a 
> cigar factory and what may be the remnants of an exploded dynamite 
> factory.  When that went up nearly 20 workers were killed.  The area near 
> my research site was at some point planted to regular rows of white pine 
> trees that are now beginning to die out.  All this indicates that the site 
> overall has suffered considerable human disturbance.  Trillium on the 
> steep glen sides were probably the source of seed that repopulated 
> disturbed areas.  In other words much of Shenk's ferry is the result of 
> active trillium colonization and reproduction.  Because of the
> width of the river, farming in the uplands, and rahter abrupt changes in 
> the underlying geology the trillium populations - particularly at Shenk's 
> ferry - would be genetically isolated.  The result of isolation and rapid 
> sexulal propagation (rapid that is for trillium) is a way of establishing 
> a local form and bringing out variation in form.
> The possibility of geologic influence needs a bit more consideration too. 
> As one goes North along the river, I believe that rock types appear that 
> are distinctly more acidic than the bedrock at Shenk's Ferry.  Acidic 
> conditions favor the red Trillium erectum.  Introgression of forms would 
> be most likely to happen near where there is a change in the acidity of 
> the country rock.  The Harrisburg site is more likely such an area than is 
> the Shenk's Ferry location.  Then to complicate things more there is 
> glaciation.  The ice did not reach Harrisburg or Shenk's Ferry, but the 
> isostatic uplift caused by glacial weight further North raised the land 
> level along the Southern Susquehanna (and Potomac) enough to allow the 
> river to create a canyon - most of which is now used for hydropower.  This 
> rise in elevation also rejuvinated side streams and left "benches" of 
> aluvial soil still visible at Shenk's Ferry.  These features were probably 
> more fertile and contain more available Ca and M
> g which the flexipes types of trillium seem to like.
> Certainly hybridization is possible and is probably responsible for the 
> color swarm near Harrisburg. but at Shenk's Ferry I think that other 
> historical factors are involved as well.
> My gracious - I am beginning to go on near as long as Richard used to.
> John Gyer  Clarksboro  NJ USA

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