Identifying Solidago altissima & Solidago canadensis

Modified from Flora of North America, Minnesota Wildflowers, Weakley 2018, Flora of the Chicago Region 2017.

Solidago altissima subsp. altissima Solidago altissima subsp. gilvocanescens Solidago canadensis var. canadensis Solidago canadensis var. hargeri
Range and prevalence in North America: Broad. Most of eastern North America and some spots in the west (map). Most common species, dominating old-fields. Midwest/Great Plains (map). Begins replacing S. altissima subsp. altissima when moving toward the Great Plains. Upper Midwest, northeastern North America. (map), but "Solidago canadensis is cultivated and introduced in more western states" (FNA) Eastern Great Plains, Upper Midwest, northeastern North America (map), but "Solidago canadensis is cultivated and introduced in more western states" (FNA)
Flowerhead shape: Messier, spikes of flowerheads not so neat; can be taller than wide Messier, spikes of flowerheads not so neat; can be taller than wide ? Graceful, neatly arranged lateral spikes; pyramid wider than tall
Involucre: 3-4.5+ mm tall 2-3 mm tall 1.7–2.5 mm tall
(apparently sometimes 3 mm)
1.7–2.5 mm tall
(apparently sometimes 3 mm)
Phenology (Chicago Region): Later: August 28 - October 22 ? Earlier: July 19 - September 19 Earlier: July 19 - September 19
Pappus: Pappus hairs >2.4 mm long Pappus hairs >2.4 mm long Pappus hairs <2.3 mm long Pappus hairs <2.3 mm long
Stem: Usually short-hairy throughout Usually short-hairy throughout Mid to proximal stems hairless or just sparsely hairy Mid to proximal stems sparsely to moderately hairy
Big round stem galls: Got'em Got'em Don't got'em (?)* Don't got'em (?)*
Foliage: -Grey-green tone
-Leaves thicker, firmer
-Entire or with few, small teeth, mostly upper half
-Hairy underside
-Upper surface hairs rough with minute bulbous bases
-Grey-green tone
-Leaves thicker, firmer
-Entire or with few, small teeth, mostly upper half
-Hairy underside
-Upper surface hairs short, curved, spreading
-Not grey-green
-Leaves thinner, more lax
-More coarsely toothed throughout
-If hairy, only on veins below
-Not grey-green
-Leaves thinner, more lax
-More coarsely toothed throughout
-Hairy underside

*Conflicting info in FNA and Flora of the Chicago Region, the latter of which says stem galls do occur on both S. altissima and S. canadensis.

Posted on October 13, 2018 04:16 AM by bouteloua bouteloua

Comments

Wow this is awesome!

Posted by wdvanhem over 5 years ago

Are you just an HTML pro or is there an easy way to make tables that I don't know about?

Posted by wdvanhem over 5 years ago
Posted by wdvanhem over 5 years ago

Super easy now that Ken-ichi fixed the HTML table formatting. Here is a basic template you can use to make something like this:

<table>
<tr>
  <th>This is the header, cell 1-1</th>
   <th>Header, cell 1-2</th>
   <th>Header, cell 1-3</th>
</tr>
<tr>
   <td>First row, cell 2-1</td>
   <td>First row, cell 2-2</td>
   <td>First row, cell 2-3</td>
</tr>
</table>

More on HTML tables: https://www.w3schools.com/html/html_tables.asp
I think the site admin do have eventual plans to make journals more blog-like, with easy buttons for formatting like in Word or Wordpress.

Posted by bouteloua over 5 years ago

This is so helpful!

Posted by ddennism over 5 years ago

This is really helpful!

Posted by tanyuu over 5 years ago

Interesting. So W&R's key, which only differentiates canadensis and altissima by involucre length (<3 vs >3 mm), seems to be grossly misleading.

Posted by elfaulkner over 5 years ago

@elfaukner - as far as I can tell, that's based on the assumption (also present in Flora of Michigan books' key) that all altissima is hexaploid (vs. all canadensis being diploid), which is probably true most of the time for easternmost states, but even then not all the time.

Posted by ddennism about 5 years ago

also, I suspect that involucre lengths measured in the field are generally a bit longer than after pressing and drying (which is where the numbers above mostly come from); at least, my in-the-field-measurements always seem to be on the high side when every other character points to a particular species

Posted by ddennism 7 months ago

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