R. davidii

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Expand view Topic review: R. davidii

Re: R. davidii

by Karl K » Fri May 31, 2019 5:14 pm

Here is a comment about R. carolina that might be useful.

Bull. Torr. Bot. Club 14(12): 253-256 (Dec 1887)
Remarks on the Group Carolinae of the Genus Rosa
By G. N. Best, M.D.
The mature fruit has not received the attention it deserves; likewise the seed. I am satisfied that from them both important aids can be derived in the differentiation of species. In the early part of winter the hips of Rosa Carolina wither and wrinkle, forming a short but distinct neck; the remaining species of the group Carolinae, on the other hand, so far as my observation goes, continue plump until the following spring. By this character alone, and especially when taken conjointly with the seed, which is smaller than in either of the other species, Rosa Carolina may be known even when divested of flowers and leaves. In like manner, as the result of close study, the fruit and seeds may afford the means of distinguishing other species and putting them on a more permanent basis.
http://bulbnrose.x10.mx/Roses/breeding/ ... s1887.html

Re: R. davidii

by Karl K » Tue May 14, 2019 5:35 pm

tsilvers wrote:
Tue May 14, 2019 4:01 pm
Hi Karl,
I just planted palustris scandens. Is this the same as plena???
Tom,
I just looked up scandens on HMF. It does look like plena, but I won't express an opinion without seeing them together.

The San Jose Heritage garden is not even vaguely swamp-like. It is hot in the summer. The plants are irrigated, but palustris plena got no more water than other roses, so far as I could tell.
Karl

Re: R. davidii

by tsilvers » Tue May 14, 2019 4:01 pm

Hi Karl,
I just planted palustris scandens. Is this the same as plena???
Whatever the case, the ForestFarm "davidii" is VERY different from scandens and both other collected palustris that I grow (one from very close to home and the other from about 4 hours east). It's also very different from all of the North American tetraploids I've grown.
You're so right, that it's very tough to ID from pictures. But in spite of the difficulty, I'll still try to get some better pictures to add to this puzzle. ;)
Thanks, Tom

Re: R. davidii

by Karl K » Tue May 14, 2019 11:45 am

tsilvers wrote:
Mon Apr 29, 2019 6:35 am
found another old picture of the rose purchased as davidii from ForestFarm
Slide4.JPG
whatever it is, I've been enjoying working with it! :)
Tom,
I won't try to identify a species from a couple of pictures, but your "davidii" sure looks like the Rosa palustris plena I photographed at the San Jose Heritage.
Image
And more pics:
http://bulbnrose.x10.mx/Roses/Rose_Pict ... plena.html
Karl

Re: R. davidii

by jbergeson » Tue May 14, 2019 9:46 am

And I just noticed the similarity in the names...someone could have scribbled "R DAV" on a tag.

Re: R. davidii

by MidAtlas » Mon May 13, 2019 9:28 pm

I noticed that some of the R. davurica photos on HMF appear to be misidentified, and others are at least questionable--those with obvious R. rugosa characteristics might just be R. x kamtschatica. The straight species as I know it (I'm familiar with one directly wild-collected clone) is upright and fairly thin-caned, too. The Forestfarm plants' images bear a much greater resemblance to that plant than most of the HMF images seem to.

Stefan

Re: R. davidii

by tsilvers » Mon May 06, 2019 1:06 pm

Yes, thanks MidAtlas/Stefan!
I looked at the davurica pictures on HelpMeFind and elsewhere and I agree, it definitely looks closer to the plant some of us are growing labeled as davidii.

And it's pretty healthy here too, Joe, whatever it actually is.
Everything is healthy this time of year, but it's usually pretty clean later in the summer too.
Here's how it currently looks here in Maryland.
davidii.JPG

Re: R. davidii

by jbergeson » Tue Apr 30, 2019 5:07 pm

Thanks, MidAtlas, for the alternate idea.

One of the commenters on HMF said this:

"Rosa marretii, and Rosa amblyotis are the two synonyms of this rose. The species is a member of the Cinnamomeae and closely allied to Rosa Cinnamomeae its self. This species is one of the parents of parents of Thérèse Bugnet."

Which might explain why both this rose and Therese Bugnet have colored stems. However, none of the roses pictured under R. davurica on HMF have that highly upright, wispy habit.

Is yours pretty healthy, there, Tom?

I take all species denotations with a grain of salt...it would be more accurate to say "my" R. davidii and "my" R. carolina.

Re: R. davidii

by MidAtlas » Tue Apr 30, 2019 1:41 am

R. davurica might be a closer match to this FF material. I would agree that these growing season photos don't look much like any of the North American species.

Re: R. davidii

by tsilvers » Mon Apr 29, 2019 6:35 am

found another old picture of the rose purchased as davidii from ForestFarm
Slide4.JPG
whatever it is, I've been enjoying working with it! :)

Re: R. davidii

by tsilvers » Mon Apr 29, 2019 6:31 am

Oh and I forgot to mention, the hips definitely don't look like the ones on HelpMeFind.
They're not so elongated but more rounded. But they also don't look like virginiana or carolina hips I've seen.
I'll try to get pictures of those this season too.

Re: R. davidii

by tsilvers » Mon Apr 29, 2019 6:24 am

Here's an old picture I found of the first plant I had years ago. The new one looks very similar. Both were from Forest FArm Nursery. I don't know what species this really is, if not davidii, but it sure doesn't look like any virginiana or carolina that I've seen.
Slide1.JPG
I'll try to get some better bloom pictures this season.

Re: R. davidii

by Karl K » Mon Apr 29, 2019 1:17 am

http://www.efloras.org/florataxon.aspx? ... =242417152

The majority of plants determined as Rosa virginiana from the Allegheny and Appalachian mountains (for example, in West Virginia) and from the Midwest (for example, Indiana) are R. carolina subsp. subserrulata. In the eastern United States, putative hybrids and their introgressants with R. carolina subsp. carolina occur from Massachusetts to New Jersey and, rarely, south or north of these states. These are the nothospecies R. ×novae-angliae W. H. Lewis.

Re: R. davidii

by Jwindha » Sun Apr 28, 2019 11:56 pm

I have the same “davidii” from Forest Farm and it is definitely not R. virginiana.

Re: R. davidii

by Karl K » Sun Apr 28, 2019 9:16 pm

I have to make a correction to Erlanson's 1934 key to Rosa carolina. She wrote, "Prickles, if present, usually terete." This agree's with Michaux's "acicularibus" (having acicles).
However, she neglected to mention the paired, hooked/curved infrastipular prickles. Michaux wrote, "aculeis stipularibus binis".
Karl

Re: R. davidii

by rikuhelin » Sun Apr 28, 2019 1:43 am

My R. carolinas are 2 to 3 times taller than my R. virginianas and canes tall and thin (5ft max so far). Latter more bushy and squat like K excerpts (2 to 3 feet). As labelled by Cornhill - vary from 3 to 5 years old. No mistaking them on height form and bloom size criteria in a side by size comparison in my garden if given only 2 possible solutions to the ID equation.

Re: R. davidii

by Karl K » Sat Apr 27, 2019 4:31 pm

jbergeson wrote:
Sat Apr 27, 2019 1:18 pm
It is not similar to my supposed R. virginiana, which are in turn nearly indistinguishable from R. carolina (both of those two came from Lawyer Nurseries).
Erlanson (1934) published a key to American roses.
http://bulbnrose.x10.mx/Roses/breeding/species.htm

R. virginiana: Stems stout, much branched. Suckers few, rarely flowering in first season. Leaflets firm and elliptic. Bristles at base and on new shoots, prickles flattened or absent. Teeth 9-30 (av. 14). Stamens 120-155. Newfoundland to eastern Pennsylvania. [stamens ave. 140]*

R. carolina: Stems usually slender, often bristly to tips, if stout usually simple; often decumbent or bending after first season. Prickles, if present, usually terete. Many suckers which often flower with terminal corymbs after main flowering period. Highly variable and "weedy" species. Leaflets mostly 7, highly varied in shape and texture. Teeth coarse, 5-21, av. 12. Stamens 65-130, av. 105. Hypanthium glandular of smooth.

Re: R. davidii

by jbergeson » Sat Apr 27, 2019 1:18 pm

The blossoms on this plant are small with thin, short-lived petals. I think there is a good chance it has been misidentified.

It is not similar to my supposed R. virginiana, which are in turn nearly indistinguishable from R. carolina (both of those two came from Lawyer Nurseries).

It is actually closest to my R. acicularis (from Lawyer), which have thin wispy stems and appear to be diploid. Very different from Robert Erskine's Aurora, which was supposedly a selection of acicularis.

Re: R. davidii

by Karl K » Sat Apr 27, 2019 12:19 am

Rosa davidii is reportedly closely allied to R. macrophylla. In fact, it has even been regarded as a variety of that species.

Here is a characteristic that should distinguish the two: exserted styles.

Rosa davidi Crép.
Bull. Soc. Roy. Bot. Belgique xiii. (1874) 253.
Si les styles sont normalement saillants, si leur exsertion n'est pas un accident dû à l'une ou l'autre cause, on peut ranger cette forme parmi les Synstylées.
If the styles are normally projecting, if their exsertion is not an accident due to one or another cause, one can arrange this form among the Synstylae.
https://www.biodiversitylibrary.org/ite ... 9/mode/1up

Exserted styles and rimmed pendulous hips (among other traits), explain why Hurst diagnosed R. davidii as AAEE. The salient characters of the species might be assembled by crossing R. macrophylla and R. multiflora, for example.
https://www.helpmefind.com/rose/l.php?l=21.328304

Re: R. davidii

by MidAtlas » Fri Apr 26, 2019 8:48 pm

Where I work, I had ordered a plant of R. davidii from a nursery (not Forestfarm, but another Pacific NW nursery, so there's a good chance these are the same clone), and determined soon after receipt that it was misidentified. I tentatively determined the plant as R. virginiana, but have not taken a close look in a number of years to see if I would still agree with that conclusion.

Stefan

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