Below are listed the hybrids involving the three micro sinningia species:
This listing does not yet include the recently discovered micro species S. minima. To my knowledge, there have been no hybrids with this species -- so far.
The listing also does not include the classical miniature sinningias, such as S. 'Cherry Chips', S. 'Super Orange', and S. 'Mercury', because I have little information on their (complex) ancestry. Nor are the modern hybrids (such as David Harris's Ozark series) included, again because I don't know their family trees. What I focus on in this page is hybrids that can be traced back to the species.
I am sure this list is incomplete. I will keep updating it as I find more information.
Linda Zillich's micro-mini site offers for sale both micro sinningia plants (within the USA) and her useful booklet on growing them.
Most miniature sinningia hybrids (and all the classical ones like 'Super Orange', 'Mercury', and 'Cherry Chips') involve S. pusilla or S. concinna as ancestors. The hybridizer's arsenal now includes S. muscicola. Plants derived from crosses between the three micro species are just about as small as those species, and are usually known as "micro-minis", although the "mini" in that expression is pretty much redundant. The micros include some varieties within S. pusilla, such as S. pusilla 'White Sprite' (GRW picture) and Sinningia 'Snowflake'.
Sinningia 'Bright Eyes' (by Carl Clayberg, 1964) is S. (pusilla x concinna) x pusilla. Because this cross was done before the official registration date (1966) of S. 'Wood Nymph' (which is S. pusilla x concinna), it is likely that Clayberg independently crossed those two species to get the 'Bright Eyes' parent.
This plant was grown by Leonie Mills of Australia. The picture was taken by Ruth Coulson. The plant is impressive not just for the bloom but for the striking green foliage. My micros usually have at least some yellowed leaves.
Sinningia 'Cindy' (by Tom Talpey, 1965) is S. concinna x eumorpha. Because it is a cross between two different clades, Sinningia 'Cindy' is sterile, but Sinningia 'Cindy-ella' is apparently a fertile tetraploid form.
Sinningia 'Cupid's Doll' (by Ruth Katzenberger, 1966) is S. 'Ramadeva' x 'Dollbaby'. Both parents are probably tetraploid S. pusilla hybrids.
Sinningia 'Dollbaby' (by Ruth Katzenberger, 1963) is S. pusilla x eumorpha. Because it is a cross between two different clades, S. 'Dollbaby' is sterile, but there is apparently a tetraploid form which is fertile. (That's according to the AGGS Sinningia register, but it may be that the plant distributed under the 'Dollbaby' name is the tetraploid.)
External link: GRW picture.
Sinningia 'Freckles' (by Carl Clayberg, 1966) is S. hirsuta x concinna. Because it is a cross between two different clades, S. 'Freckles' is sterile, but S. 'Hircon' is apparently a fertile tetraploid form.
External link: GRW picture.
Sinningia 'Krishna' (by Frances Batcheller, registered 1973) is S. 'Ramadeva' "line bred" (according to the Gesneriad Hybrids Register). Presumably this means that S. 'Krishna' is the result of selfing S. 'Ramadeva'.
Sinningia 'Oengus' (by Frances Batcheller, registered 1973) is S. (concinna x schiffneri) x 'Krishna'. Thus this hybrid has both S. concinna and S. pusilla in its background.
As usual, however, I must be skeptical about its ancestry. S. concinna x schiffneri would have to be sterile. The two species are so far apart, I would be surprised if even the standard appeal to tetraploidy would work here. I have never seen either S. 'Oengus' or its putative ancestor S. concinna x schiffneri.
Sinningia 'Pink Petite' is S. pusilla x leucotricha, registered by Carl Clayberg in 1965. See also S. 'Ramadeva'.
Sinningia 'Quasar' is S. pusilla x conspicua, registered by Al Wojcik in 1993. I presume it does not have a supermassive black hole at its center, but I have not seen it, so I cannot be sure.
Sinningia 'Ramadeva' (by Frances Batcheller, registered 1973) is S. pusilla x leucotricha. See also S. 'Pink Petite'.
Because this cross spans two different clades, the outcome should be sterile. However, the Gesneriad register shows several crosses with S. 'Ramadeva' as parent, so it is likely that this one is a fertile tetraploid form.
For instance, S. 'Benten' was registered by Frances Batcheller in 1973, as S. 'Ramadeva' x barbata, and S. 'Kore' as S. 'Ramadeva' x richii. I have to say, hybridizers were tougher in those days. You get a fertile tetraploid hybrid of S. leucotricha and S. pusilla, and right away you cross it with S. richii and S. barbata? No wimpy S. eumorpha or S. cardinalis crosses for Mrs. Batcheller, no sir.
This plant looks a lot like S. concinna. The flower is just about the same size or a bit larger. This spotting on the face and tube of the corolla is not as intense as in S. concinna. According to Carolyn Ripps, S. 'Razzmatazz' is "a hybrid made by the late Kiku Shimomura of the Greater NY chapter. It has been around for more than 20 years" [written in 2009].
From the picture, it can be noted that it lacks the "spur" on the corolla tube characteristic of S. pusilla.
This plant was one of the micros I inherited from the late Fred Stryker of San Jose, California.
(The flower is more purple than this. It is really hard to capture accurate purples with a digital camera.)
The Gesneriad Society Sinningia Register states that Sinningia 'Snowflake' was registered by Carl Clayberg in 1971, as a cross between Sinningia pusilla 'White Sprite' and an unnamed mutant (of S. pusilla?).
Peter Shalit did this cross. He reported that he grew out about 30 F1 seedlings, all of which appeared to be sterile except for one. The seedlings from that plant were very uniform and similar to the F1 but larger, which led him to believe they are fertile tetraploids. These plants are similar to the muscicola parent, which makes him reluctant to release them even though they reproduce readily from seed. Dale Martens has grown some progeny seedlings and got no white-flowered plants (one would expect some white-flowered plants if the plants were not tetraploid).
John Boggan did this cross. It is Sinningia concinna x 'Snowflake'.
Sinningia 'Tinkerbells' (by Elena Jordan, registered 1971) is S. concinna x aggregata. According to Michael Riley, in a message posted on Gesneriphiles, this hybrid was made on a New York windowsill, that being the only growing conditions available to the hybridizer. According to the legend recounted by Carolyn Ripps, there was one seed from the cross, and this was the result. In hybridizing: do not throw away anything.
Sinningia 'Toad Hall' (by Jim Steuerlein) is S. muscicola x conspicua. It is more conspicua-size than muscicola-size, but it does have some of the conspicua fragrance.
See the page for this hybrid.
Sinningia 'Wood Nymph' (by Lyndon Lyon, 1966) is S. pusilla x concinna. Because it is a cross between two species in the same clade, S. 'Wood Nymph' is fertile. (Or rather, not quite sterile, according to Peter Shalit.) S. 'Ruffled Wood Nymph' is S. 'Wood Nymph' back-crossed to S. concinna.
External links: GRW pictures of S. 'Wood Nymph' and S. 'Ruffled Wood Nymph'.
Sinningia 'Yma' (by Jim Steuerlein) is S. muscicola x bullata. It does have some of the bullate leaf texture from the bullata parent, but none of the wool on the stems and under the leaves.
Like the Sinningia bullata parent, my plant of this hybrid tends to sprawl.