Just searching on "C.D. Reimers" turned up mostly hits on a more recent person of the name. Adding "the Telegram" made a bit difference. And as usual, wt1 came through with some useful information.
Now that I know what I'm looking for, I've found further information. He joined the A.P.A. in 1892, and soon thereafter the following advertisement appears:

He would have been 20 at the time. Fast forward to 1936 and he appears to have created his "first cachet:"

BTW, these are current listings, and the first one is a hoot, from none other than "billsbargainstamps." For a third of what he wants for a block of four on the cover, you can get a plate block on the cover.
I'm assuming this is the same C.D. Reimers. It is curious that for someone so well known in Fort Worth that I cannot locate an obituary or other notice of the date of his death.
Basil