Eriogonum ID?

I like to make side-by-side visuals, helps to arrive at conclusions, so here are the two drawings put together; E. androsaceum and E. ovalifolium var. nivale.  Of course, you believe you might be seeing E. ovalifolium var. depressum, I'm not sure how it varies from the depicted var. nivale.

There are some aspects a bit different.  The involucre in E. androsaceum is more narrowly campanulate (cone-shaped) and without any sharp teeth at the apex, whereas in E. ovalifolium var. nivale the involucre is more openly campanulate and with 5 pointed teeth... that seems a real characteristic, involucre shape playing a key role in Eriogonum identification.

Regarding leaves, in E. androsaceum the leaves have the margins rolled under rendering a much narrower look to the leaves, whereas in E. ovalifolium var. nivale the basal leaves are "roundish", and without the margins rolled under have a more rounded or spoon-shaped leaf look.

You are correct, these detailed drawings both show stipes, so that is probably an unreliable characteristic.  By the way, I'll be sending James Reveal links to Cohan's mystery Eriogonum in Alberta.  You mentioned "E. umbellatum also occurs in the area at slightly lower elevations, but I think I recognize that one"... I'm not sure I always would, there are 41 varieties in Flora of North America, that must be an all time record for any plant species!

Thanks for digging into the details, Mark.
Eriogonum ovalifolium var. nivale occurs in BC, apparently, but not in Alberta, according to Eflora of NA.  Eflora of NA says that the only E. ovalifolium occurring in Alberta is var. depressum.  Unfortunately, the eFlora of NA description of var. depressum does not have a lot of detail about the involucre, to allow a comparison between it and var. nivale, or between var. depressum and E. androsaceum.  There seems to be quite a lot of variability in leaf shape even within a variety, viz. Moss/Packer's description of leaf shape for E. ovalifolium.

Interestingly, USDA Plants agrees with Flora of Alberta (that we have only var. ovalifolium), and not with Eflora of NA (which says we have only var. depressum):
http://plants.usda.gov/java/profile?symbol=EROVO5
http://plants.usda.gov/java/profile?symbol=EROVD

BTW, I am happy to believe it is var. depressum that we have, as it seems the description fits better than var. ovalifolium... (and also that these plants are, therefore, E. ovalifolium var. depressum).

Can anyone at least confirm that this plant is E. ovalifolium, rather than E. androsaceum?

McDonough wrote:

By the way, I'll be sending James Reveal links to Cohan's mystery Eriogonum in Alberta.

Would you mind sending mine as well please?  I have a ton of other photos of this plant, which I'll examine re. the involucre details.  As I've mentioned, I think Cohan's "mystery eriogonum in Alberta" is this plant.

McDonough wrote:

You mentioned "E. umbellatum also occurs in the area at slightly lower elevations, but I think I recognize that one"... I'm not sure I always would, there are 41 varieties in Flora of North America, that must be an all time record for any plant species!

Well, I think I can recognize it here, where we only have var. subalpinum (according to Flora of Alberta), and only in relation to the other eriogonums we have, but maybe I'm fooling myself!  :D

Skulski wrote:

Thanks for digging into the details, Mark.
Eriogonum ovalifolium var. nivale occurs in BC, apparently, but not in Alberta, according to Eflora of NA.  Eflora of NA says that the only E. ovalifolium occurring in Alberta is var. depressum.  Unfortunately, the eFlora of NA description of var. depressum does not have a lot of detail about the involucre, to allow a comparison between it and var. nivale, or between var. depressum and E. androsaceum.  There seems to be quite a lot of variability in leaf shape even within a variety, viz. Moss/Packer's description of leaf shape for E. ovalifolium.

Interestingly, USDA Plants agrees with Flora of Alberta (that we have only var. ovalifolium), and not with Eflora of NA (which says we have only var. depressum):
http://plants.usda.gov/java/profile?symbol=EROVO5
http://plants.usda.gov/java/profile?symbol=EROVD

BTW, I am happy to believe it is var. depressum that we have, as it seems the description fits better than var. ovalifolium... (and also that these plants are, therefore, E. ovalifolium var. depressum).

Can anyone at least confirm that this plant is E. ovalifolium, rather than E. androsaceum?

McDonough wrote:

By the way, I'll be sending James Reveal links to Cohan's mystery Eriogonum in Alberta.

Would you mind sending mine as well please?  I have a ton of other photos of this plant, which I'll examine re. the involucre details.  As I've mentioned, I think Cohan's "mystery eriogonum in Alberta" is this plant.

McDonough wrote:

You mentioned "E. umbellatum also occurs in the area at slightly lower elevations, but I think I recognize that one"... I'm not sure I always would, there are 41 varieties in Flora of North America, that must be an all time record for any plant species!

Well, I think I can recognize it here, where we only have var. subalpinum (according to Flora of Alberta), and only in relation to the other eriogonums we have, but maybe I'm fooling myself!  :D

I will defer to Jim but have a few comparisons based on the most recent Eriogonum ID Manual updated June 2010 and only made available to those who attended the inaugural meeting  of the  Eriogonum Society

depressum - Involucre description is '2-4 per cluster, 3-3.5 mm'
flowers 4-5mm; perianth white to rose. flowering june-august.......900-3500 m....

androsaceum - Involucre description is '1 per node, narrowly turbinate to turbinate-campanulate, 3-5 x 3-4.5 mm; filaments pilose proximately'
flowers (3.5)4-5(-6.5)mm, including 0.1-0.2 mm stipelike base; perianth pale yellow sparsely pubescent abaxially; tepals monomorphic, narrowly oblong; stamens exserted, 4-5mm; filaments pilose proximately.  Achenes light brown
flowering july-august...... 1700-2700 m.

and so forth....  have fun with this.  Signing off for now...

According to the manual mentioned by Hugh the Eriogonum flavum varieties found in Alberta are E. flavum v. flavum and  v. piperi.
The Eriogonum ovalifolium varieties are E. ovalifolium v. purpureum and v. depressum
Eriogonum androsaceum also is found in Alberta.

I have taken a few general information excerpts from the manual that we can compare to the photos.

Both the ovalifolium varieties have "Infloresences capitate branches absent"
E. androsaceum has "Infloresences subcapitate or umbellate,...."

E. ovalifolium v. purpureum  "Scapes erect tomentose"
E. ovalifolium v. depressum "Scapes often suberect to decumbent, thinly floccose"
E. androsaceum "Stems ..... aerial flowering stems ascending to erect, slender,
.....tomentose to floccose or subglabrous."

E. ovalifolium v. purpureum "Leaf blades spatulate, oblong, or obovate to oval, tomentose to floccose, margins rarely brownish."
E. ovalifolium v. depressum "Leaf blades elliptic, or infrequently oblong to spatulate, tomentose to floccose, margins not brownish."
E. androsaceum "Leaves basal, occasionally in rosettes...,tomentose: blade narrowly elliptic, densely white-lanate or grayish-tomentose abaxially, floccose and green adaxially, margins entire, usually slighty revolute."

E. ovalifolium v. purpureum "Flowers perianth white to rose or purple"
E. ovalifolium v. depressum "Flowers perianth white to rose"
E. androsaceum "Flowers ...perianth pale yellow....stamens exerted..."

I would put this under E. ovalifolium v. depressum

I will be very interested in Dr. Reveal's assessment.

Thanks John, useful to have further compilation of characteristics to tell E. androsaceum apart from ovalifolium.

I wrote to Dr. James L. Reveal, Ph.D, Professor Emeritus, University of Maryland and noted authority on the genus Eriogonum, 1) regarding the mystery Eriogonum from west central Alberta that SRGC member Cohan Fulford posted here:
http://www.srgc.org.uk/smf/index.php?topic=5641.msg170030#msg170030

...and 2) asked him to take a look at Lori's Eriogonum pics here which she believes come closest to E. ovalifolium var. depressum.

Here are his answers:

1) "All images [in Cohan Fulford's link] are of Eriogonum androsaceum  Benth. As for a distinction between E. ovalifolium and E. androsaceum all one needs to do is look at the base of the flower. In the first the rounded base of the flower is directly attached onto the pedicel; in E. androsaceum there is a short stalk ("stipe") that extends from the narrow base of the flower down to the pedicel.

Nice pictures of E. androsaceum and if you look at the narrow leaf blades that are faintly lined on the thinly and darkish tomentose upper surface that will quickly distinguish this species from the broader leaved E. ovalifolium  that is usually distinctly densely white tomentose on a smooth upper surface. The line business is something you can best see in the field as this is faint and does not really preserve on herbarium specimens. The line business is something you can best see in the field as this is faint and does not really preserve on herbarium specimens."

2) Eriogonum ovalifolium var. depressum Blank. is in Alberta, but I have seen no specimens I could assign to var. nivale that far east.

He added: "Be glad to address any questions you might have on Eriogonum"  :D

Just to add to the fun, here's a photo from Calflora of Eriogonum ovalifolium var. ovalifolium that appears to show stipes (though apparently it should not) and exerted stamens.  Is it misidentified, or am I misinterpreting the term "stipe", or... ?

http://calphotos.berkeley.edu/cgi/img_query?enlarge=0000+0000+0710+2217

Correction:  It's been established that stipes are (probably) not visible in this photo.  What I had interpreted as "stipes" are actually the pedicels.

Skulski wrote:

Just to add to the fun, here's a photo from Calflora of Eriogonum ovalifolium var. ovalifolium that appears to show stipes (though apparently it should not) and exerted stamens.  Is it misidentified, or am I misinterpreting the term "stipe", or... ?

http://calphotos.berkeley.edu/cgi/img_query?enlarge=0000+0000+0710+2217

Word of caution, watch out for the Calphotos site.  I love it, it's a great resource, but since many (most) photos are user donated, there are often misidentifications.  In the genus Allium, I have spotted some fairly obvious (to me) misidentifications among the pool of photos that Calphotos dishes up, so be cautious using this resource on a genus as polymorphous and taxonimically difficult as Eriogonum.

However, aware of the apparent contradiction in the E-Flora of BC line drawings that show both E. androsaceum and E. ovalifolium var. nivale having flowers with stipes, I have already written back to Dr. Reveal about this detail.  See response below from Dr. Reveal.

But aren't we happy about the more established fact, that what Cohan showed us is E. androsaceum, as was suspected?

McDonough wrote:

But aren't we happy about the more established fact, that what Cohan showed us is E. androsaceum, as was suspected?

I am satisfied having had time to reread this topic from start to finish - John supplied more of the detail from the ID manual and Jim's answer fills in from an informed perspective.  Now I want to see this beauty! 
I absolutely agree with Mark regarding the Calflora photos.  Gary Monroe, one of the contributors to Calflora, on the other hand, is usually spot on

Hi folks, I heard back quickly from Dr. Reveal, and he offers up a good lesson in the anatomy of an Eriogonum flower head (wish I had some fresh flowers to better understand the finer points), but after going through his examples, I think I'm starting to see the difference.

Dr. Reveal's response:
"Jeanne's image of Eriogonum ovalifolium var. nivale is correct; she is showing the flower attached directly onto the pedicel. Look at the following image of E. nervulosum: http://www.plantsystematics.org/reveal/pbio/digitalimages/004867.html
On the left side of the involucre you will see a small number of truncated pedicels denoting where the flowers were attached. You will see (at 12 o'clock) a single flower with a short stipe attached to a pedicel. The stipe is better seen on the flower (at 7 o'clock) that is slightly out of focus and on the ground. In this image of E. umbellatum var. subaridum, a species with a well-defined stipe (http://www.plantsystematics.org/reveal/pbio/digitalimages/002405.html) you can see the long stipe of the flower that is attached to the pedicel, the joint between the stipe and pedicel denoted by a dark line (see the flower on the right at 3 o'clock). (MMcD - pay particular attention to this last example, look for that dark line where one can see the juncture between a "stipe-like" attenuate base of the floret and the short connected stipe; for me, I believe I've been misinterpreting what the "stipe" actually is.)

In an image of old flowers of var. depressum (http://www.plantsystematics.org/reveal/pbio/digitalimages/003188.html) you can see the pedicels much better defined. In this image of Eriogonum ovalifolium var. williamsiae you can see how these flowers are attached onto the pedicel (http://www.plantsystematics.org/reveal/pbio/digitalimages/006883.html).

Hope this is helpful.

The next meeting of the Eriogonum Society will be near Bishop, California, next August."

Edited by L. Skulski to make the first link functional.

McDonough wrote:

I wrote to Dr. James L. Reveal, Ph.D, Professor Emeritus, University of Maryland and noted authority on the genus Eriogonum, 1) regarding the mystery Eriogonum from west central Alberta that SRGC member Cohan Fulford posted here:
http://www.srgc.org.uk/smf/index.php?topic=5641.msg170030#msg170030

...and 2) asked him to take a look at Lori's Eriogonum pics here which she believes come closest to E. ovalifolium var. depressum.

Here are his answers:

1) "All images [in Cohan Fulford's link] are of Eriogonum androsaceum  Benth. As for a distinction between E. ovalifolium and E. androsaceum all one needs to do is look at the base of the flower. In the first the rounded base of the flower is directly attached onto the pedicel; in E. androsaceum there is a short stalk ("stipe") that extends from the narrow base of the flower down to the pedicel.

Nice pictures of E. androsaceum and if you look at the narrow leaf blades that are faintly lined on the thinly and darkish tomentose upper surface that will quickly distinguish this species from the broader leaved E. ovalifolium  that is usually distinctly densely white tomentose on a smooth upper surface. The line business is something you can best see in the field as this is faint and does not really preserve on herbarium specimens. The line business is something you can best see in the field as this is faint and does not really preserve on herbarium specimens."

2) Eriogonum ovalifolium var. depressum Blank. is in Alberta, but I have seen no specimens I could assign to var. nivale that far east.

He added: "Be glad to address any questions you might have on Eriogonum"  :D

Thanks very much for doing this, Mark.

Cohan's photos include one with a side view of the inflorescense, though I don't find it to be quite close enough or clear enough to definitively see stipes.  Can anyone else confirm the presence of stipes there?   At this point, I guess I'm led to conclude then that the distinction between E. ovalifolium and E. androsaceum can be made primarily on the leaves... ?

Sorry, I'm not following...  in 2) above, was Dr. Reveal commenting on the ID of the plants in my photos (as being Eriogonum ovalifolium var. depressum Blank.??) or was he making a more general comment on the varieties that occur in Alberta, not specifically commenting on my photos?   Thanks in advance for clarifying.

Skulski wrote:

Cohan's photos include one with a side view of the inflorescense, though I don't find it to be quite close enough or clear enough to definitively see stipes.  Can anyone else confirm the presence of stipes there?   At this point, I guess I'm led to conclude then that the distinction between E. ovalifolium and E. androsaceum can be made primarily on the leaves... ?

Sorry, I'm not following...  in 2) above, was Dr. Reveal commenting on the ID of the plants in my photos (as being Eriogonum ovalifolium var. depressum Blank.??) or was he making a more general comment on the varieties that occur in Alberta, not specifically commenting on my photos?   Thanks in advance for clarifying.

It seems that there is enough foliar differences to make a distinction between the two species, but certainly closely examining the flowers helps too, I think you'd have to look VERY CLOSE at a partially pulled-apart flower head to seed the stipes if present.

By inference I think he's okay with the E. ovalifolium var. depressum ID, that's my take on it.

Let me also share a tangential identification exercise, with the genus Ophiopogon.  I was working with a guy at Plant Delight's Nursery to find a proper ID on what goes around as Ophiopogon chingii (of Hort) but that I felt was actually another species, O. umbraticola. In this exercise, one of the things that came out of it was a feature (perhaps particular to the genus Ophiopogon) referred to as "pedicel articulation", with species descriptions calling out possibilities such as proximal, middle, and distal.  Looking at closeups of the flowers, one can see a flower that narrows to an apparent pedicel, that pedicel connecting and joining to a subtended pedicel (or stipe) off the stem, often the connection at a "broken" angle, making the "pedicel articulation" a bit more apparent.  The situation in Eriogonum seems somewhat analogous.  I attach an image of the flowers of O. umbraticola, that shows that "pedicel articulation".

McDonough wrote:

Skulski wrote:

Cohan's photos include one with a side view of the inflorescense, though I don't find it to be quite close enough or clear enough to definitively see stipes.  Can anyone else confirm the presence of stipes there?  At this point, I guess I'm led to conclude then that the distinction between E. ovalifolium and E. androsaceum can be made primarily on the leaves... ?

It seems that there is enough foliar differences to make a distinction between the two species, but certainly closely examining the flowers helps too, I think you'd have to look VERY CLOSE at a partially pulled-apart flower head to seed the stipes if present.

Lori/Mark - the image is not clear enough for me to confirm stipe presence.  Regarding id of eriogonum, one of the challenges with had in the classroom session with Dr. Reveal in Reno, was the small size of some of the features in eriogonum.  We were forewarned to be sure to bring at least a 14x lens..  Sometimes the stipe joint was so subtle as to be easily overlooked.  I believe Weiser will confirm my observations.  We did have a few lab microscopes available to us which made identification a bit easier.  I personally carry a 10x. 14x, and 20x lens when in the field - it helps to have the ability to see these smaller features.  We were also advised to bring a dissecting needle or sharp blade for taking apart the flower heads -

For exercises as fun as this one, I have been going back to the subgenera to start identification.  In our example, therefore, I start with E. ovalifolium var. depressum and see that it is in subgenus Eucycla and E. androsaceum is in subgenera Oligogonum.  Although the difference in the leaves is certainly a clue, I find numerous other distinctions in the two subgenera - without a sample to tear apart I believe for me an identification would be more an educated guess than a positive identification - It's good to have Jim so available and willing to share his lifetime of experience at this point.

You haven't started barcoding the plants yet to confirm the species? This is not a joke, as you may think!
http://en.wikipedia.org/wiki/DNA_barcoding

I'll be sure to take my bar code reader out with me next time!  ;)

What image is being referred to below?  Is it the drawing at eFlora of BC or ... ?

McDonough wrote:

Dr. Reveal's response:
"Jeanne's image of Eriogonum ovalifolium var. nivale is correct; she is showing the flower attached directly onto the pedicel.

Hoy wrote:

You haven't started barcoding the plants yet to confirm the species? This is not a joke, as you may think!
http://en.wikipedia.org/wiki/DNA_barcoding

Interesting article - a glimpse to the future!  On the other hand, it's nice to see all the folks on this thread running to their references and honing up on their skills!

As Hugh pointed out we dissected a lot of flowers in the class peering through loupes and hand lenses. Of course it always helped to have a steady hand and a botanist setting beside you as a reference source. ;)

Skulski wrote:

What image is being referred to below?  Is it the drawing at eFlora of BC or ... ?

McDonough wrote:

Dr. Reveal's response:
"Jeanne's image of Eriogonum ovalifolium var. nivale is correct; she is showing the flower attached directly onto the pedicel.

He is referring to the drawing in eFlora of BC.

Rewritten (my interpretation of what was the stipe and what was the pedicel was backwards):  In that one photo of E. umbellatum var. subaridum that Dr. Reveal had a URL for, looking into the flower head, viewing the flower on the right at 3 o'clock, you can detect a very subtle line or joint below the flower, and a little bit further down the narrow stipe another slightly darker line indicating the joint with the pedicel.  In another link by Dr. Reveal, one can see pedicels that are left behind after the flowers with their stipes shed.  Since the stipe and pedicel are inline and continuous, it can be hard to discern if a stipe is present; so when when looking at drawings that show a floret, one doesn't really know if one is seeing a stipe, a pedicel, or a stipe-pedicel combination, because it all looks basically the same unless examined very closely.

Hugh wrote:

I personally carry a 10x. 14x, and 20x lens when in the field - it helps to have the ability to see these smaller features.  We were also advised to bring a dissecting needle or sharp blade for taking apart the flower heads -

I can envision the Eriogonum Posse, Hugh at the head, donning a leather holster with gleaming 10x-20x caliber lenses, dissecting needles, and a bar-coder45, and a bottle of scotch, wrangling wild buckwheat IDs ;D  I'd like to get some of this gear myself and come out for the next Eriogonum meeting in CA.

Great!  Thanks for the explanation!

MMcD edit:  Photo removed as I had misinterpreted and misled Lori on the stipe and pedicel relationship.  See further in this topic for an annotated photo showing the stipe and pedicel relationship.

Skulski wrote:

Great!  Thanks for the explanation!

So, to check if I understand what has been said, is the annotation that I added to Dr. Reveal's photo (below) correct?

Yes!  I believe so.  No, my interpretation was backwards, so it is the other way around,
see:  http://nargs.org/smf/index.php?topic=493.msg5099#msg5099

Don't you wish that the floras would show a diagnostic photo or drawing for each genus, to helps its users to understand the important criteria for each genus; to help them understand terms used in the keys.

Okay, very interesting and thanks again!  (Reminds me of the difference between Campanula and Adenophora...)

McDonough wrote:

Don't you wish that the floras would show a diagnostic photo or drawing for each genus, to helps its users to understand the important criteria for each genus; to help them understand terms used in the keys.

That would be a terrific help!

McDonough wrote:

I can envision the Eriogonum Posse, Hugh at the head, donning a leather holster with gleaming 10x-20x caliber lenses, dissecting needles, and a bar-coder45, and a bottle of scotch, wrangling wild buckwheat IDs ;D  I'd like to get some of this gear myself and come out for the next Eriogonum meeting in CA.

Funny Mark - I have actually been compared to Billy the Kid so you may have me on the wrong side of the Eriogonum Law.

Let me pipe in again regarding the stipe issue - in some cases it is very easy to see that a stipe exists and in others it is so subtle as to be barely evident so don't feel like the Lone Ranger Lori. 

In the classroom and in the ID book we did indeed have a few diagnostic drawings.

It has been my intent since Reno to supply a set of diagnostic drawings on the Eriogonum Web site.  I will probably be the one to do the drawings so that there is continuity (rather than a collection of disparate drawings).  My vision is to start at the root and proceed up to the flower - if I can code it properly I would like to have a 'mouse over' effect to show some of the alternatives in a given structure (for example, different root types).

Gary Monroe, one of the main contributors of images of Eriogonum on Calflora, in a recent correspondence to me, said that he will be adding photos with some morphological features highlighted (and annotated?). 

Sorry to interupt you, but isn't it the other way round? I mean Lori's picture with the writings.
I have thought that the pedicel is the stem that connect the whole flower to the rest of the plant (and no part of the flower itself), and that the stipe in flowering plants often is what connect the ovary to the rest of the flower and therefore a part of the flower tissue! (And you will find it inside the perianth)

McDonough wrote:

I can envision the Eriogonum Posse, Hugh at the head, donning a leather holster with gleaming 10x-20x caliber lenses, dissecting needles, and a bar-coder45, and a bottle of scotch, wrangling wild buckwheat IDs ;D  I'd like to get some of this gear myself and come out for the next Eriogonum meeting in CA.

if this is the gear and buckwheat is the purpose I hope to be invited!

Quote:

Gary Monroe, one of the main contributors of images of Eriogonum on Calflora, in a recent correspondence to me, said that he will be adding photos with some morphological features highlighted (and annotated?).

I count Gary as a personal friend we often take botanizing hikes together with the Nevada Native Plant  Society when he is available. He is a major contributor of photos covering all genus to Calflora, USDA Plants Database and actively involved with the Jepson Manual. Gary does his best to positively identify and confirm all of his shots.  I have seen Gary's photos depicting what to look for when locating a stipe on Eriogonums. He had me take a look to see if I thought they showed the features clearly. They are very good.

Here is a shot of Gary at 9700' on Slide Mountain taking a photo of Eriogonum  rosense. 
.

Hoy wrote:

McDonough wrote:

I can envision the Eriogonum Posse, Hugh at the head, donning a leather holster with gleaming 10x-20x caliber lenses, dissecting needles, and a bar-coder45, and a bottle of scotch, wrangling wild buckwheat IDs ;D  I'd like to get some of this gear myself and come out for the next Eriogonum meeting in CA.

if this is the gear and buckwheat is the purpose I hope to be invited!

Damn right you're invited!  Have gear, will travel...

Hoy wrote:

Sorry to interupt you, but isn't it the other way round? I mean Lori's picture with the writings.
I have thought that the pedicel is the stem that connect the whole flower to the rest of the plant (and no part of the flower itself), and that the stipe in flowering plants often is what connect the ovary to the rest of the flower and therefore a part of the flower tissue! (And you will find it inside the perianth)

Sorry if there was confusion.  Try this definition of stipe;
stipe: Here defined as an elongated extension of the receptacle positioned between the pedicel and the base of the short perianth-tube. The stipe is round in cross-section and more or less uniformly thickened for its entire length. The stipe is a diagnostic feature of Eriogonum subg. Eriogonum and subg. Oligigonium. A decidedly, albeit slightly, winged stipe is seen in two species of subg. Eucycla, E. crocatum and E. saxatile. This feature is otherwise absent from Polygonaceae. In a few species of subg. Oligigonium (e.g., E. lobbii) the stipe can be nearly obsolete, especially in high elevation populations. 
Yes, it is inside the perianth and yes, your description of the pedicle is correct.

As a point of reference and really good reading for eriogonites (eriogophyles?) go to the Eriogonum website to see an excellent 5 part treatise by Jim Reveal on morphological features of Eriogonum (starting with the Feb. 2009 issue).  Also, there is a very complete glossary on the website (stipe definition above taken from this glossary).

To quote the song by Michael Stipe (yes, Stipe) 'everybody hurts.. some time'.

My apologies to everyone, sometimes I can be such a dufus: http://www.thefreedictionary.com/Dufus

I have misinterpreted the whole stipe vs. pedicel thing again, but I think maybe it has finally sunk in.  I have reread Dr. Reveal's explanation and photo links for like the 8th time, and I concur with Trond, and Hugh, that I have it backwards.

So, I marked up another copy of Dr. Reveal's photo of E. umbellatum var. subaridum, identifying the stipe and pedicel.  I have a 50/50 chance of getting it right this time around :rolleyes:.  Hugh and John, care to comment on the photo, did I get the flower part identifications right?  If so, we can go back and fix previous misinterpretations, and sorry Lori for misleading you too.

I would really like to find a simple drawing, and enlarged view of eriogonum flowers, to point out and name the various parts; Hugh your idea of creating such drawings and making them available would be a fantastic aid towards Eriogonum keying and identification.  I went through all of the Eriogonum Society newsletters, but didn't really find anything about the "stipes" but I was skimming through quickly and may have missed it, good stuff in those newsletters by the way:
http://eriogonum.org/index.php?option=com_content&view=article&id=48:new...

Mark
Yes you have it right. The stipe is usually the same diameter as the pedicel with the faint demarcation line. In some species the stipe is almost non existent, as Hugh pointed out. The presence of a stipe or the absence is one of the first keys that help lead you through the subgenera classifications. The length of the structure can help break the two subgenera in which it exists further. Or it's absence will send you off chasing down a winding path though the other five subgenera.

Weiser wrote:

Mark
Yes you have it right. The stipe is usually the same diameter as the pedicel with the faint demarcation line. In some species the stipe is almost non existent, as Hugh pointed out. The presence of a stipe or the absence is one of the first keys that help lead you through the subgenera classifications. The length of the structure can help break the two subgenera in which it exists further. Or it's absence will send you off chasing down a winding path though the other five subgenera.

Well stated John.  Another one of the tools that the Eriogonum Posse carries is a ruler with mm markings.  Very handy in the field and study.  I have indeed gone down the wrong subgenera more than once!

Gary A. Monroe has kindly given consent, for us to use a series of photos he has produced. These fine  photos depict the parts of an Eriogonum pedicel. This series will show details from four species. 

I wish to thank Gary personally for so kindly offering these to us.

The first is Eriogonum heracleoides var. heracleoides: 4 mm stipe

The second is Eriogonum robustum: stipe < 1mm

The third is Eriogonum douglasii var. meridionale: 2 mm stipe

The fourth is Eriogonum ochrocephalum var. ochrocephalum:  without a stipe

Thanks John, very interesting, but for me it both answers some questions and raises new ones.  In the second photo, showing an Eriogonum robustum flower, how is it that the part identified as a stipe, is a stipe?  It looks just like either the somewhat narrowed base of the perianth, or at best, the receptacle itself.  Is there a physical delineation of cells or tissues separating the stipe in this instance, a joint which would separate or dehisce at a line or point of separation?

In the context of what these 4 photos show, does a stipe, when present, ALWAYS have a part called the "receptacle" at the point of juncture with the pedicel?  In the first photo (Eriogonum heracleoides var. heracleoides), why isn't the narrowed base of that perianth also considered a stipe and receptacle; maybe because there can't be more than one such pair per perianth?  This is all pretty subtle stuff!

For me, I am still trying to understand the precise definition of a stipe in the context of Eriogonum.  But these types of illustrations are exactly what is needed, thanks for posting them.

There is no physical delineation between the stipe and the perianth. The stipe is the cylindrical extention of the perianth base. (A supporting stem as you would find in say a wine glass. ) The tissues of the stipe are the same as the perianth.
As you have noted they may appear barely noticeable as in E. robusta or easy to see as in E. heracleoides.
To answer your question about why the narrow base of E. heracleoides is not considered a part of the stipe. The stipe portion of the perianth is always the same diameter as the pedicel (or very close to it). 

I know this is a little murky. It still is for me too some times.

I hope this helps a little.

Thanks for all the stipe vs. pedicel info... it becomes very clear that this is not the type of detail that is likely to be captured by casual photos!

So, it seems Cohan's photos were identified as E. androsaceum based on the leaves (as the stipe/pedicel detail was definitely not visible), while it seems mine were ID'd as E. ovalifolium, also based, evidently, on the leaves,  (as the stipe/pedicel detail is definitely not visible in my photos either).  

So, revisiting where we started some time ago... (discounting the fall colour in one photo) are these not actually the same plant? Here is a side-by-side comparison of one of Cohan's photos (left) with one of mine (right):

I can't speculate Lori, goodness knows I already misinterpreted much of the technical info, so I will confidently rely on Dr. Reveal's ID diagnosis.  But I think it has to do with those extremely subtle stipe characteristics that I've made such a mess of :), as well as some of the foliar characteristics.

But the stipes/pedicels aren't visible on any of the photos I posted...

Skulski wrote:

But the stipes/pedicels aren't visible on any of the photos I posted...

He must more than we know... I still trust his judgment.  I think he may be going on differences in the leaf characteristics.

Remember the uncertainty raised by Dr. Reveal's response which made it unclear as to whether he was commenting on the distribution of E. ovalifolium subspecies in Alberta, or whether he was actually referring to the ID of the plants I posted?

What do you see as the major foliage differences between the plants in the side-by-side comparison... ?