question: most floriferous

[Maryanne]

Marigolds ? ; -D (oh, April first was yesterday)
I think the plant you choose with those characteristics has to be in exactly the correct conditions to be able to deliver what you demand of it. I have (or had) some of the plants listed above. I obviously have conditions too cold for Phals, and cute Harella (gone) Phrag longifolium hybrid I have grows well enough, but some condition (too cold?) does not exist here to allow it to flower much - winter too long with little sun in New England maybe?
I have a Crystelle Smith, which does OK, but again, it is not in constant bloom. You will have to keep trying various plant selections and manipulating all conditions to keep that plant optimally happy.
Best of luck in your search!
Maryanne

[MrHappyRotter]

Originally Posted by Maryanne

Marigolds ? ; -D (oh, April first was yesterday)

HA! I was thinking about suggesting African violets.

[Maryanne]

Hey, I forgot to mention - I have Mormolyca ringens IOSPE PHOTOS
Which does push out a few flowers all year round. But, it is not a big showy thing, and there is only one flower to a spike. It's totally reliable, though and tolerates temperature extremes, so I keep it around ; -)
Jumellea comorensis also was pushing out a bloom year round, but lately it's taking a nose dive, and I cannot figure out why - I've had it at least 8 years (sigh)

Happy hunting,
M

[Ray]

Methinks the OP is looking for a unicorn.

[Leafmite]

Dendrobium auriculatum blooms all the time. They do not form spikes, just buds off the stem of the plant but the flowers are pretty and fragrant. Not only is it nearly always in bloom, it is easy to grow and the leaves are pretty, almost like a fern.

Phal-type Dendrobians if you are willing to be patient for a year or two while they get established in a medium that does not decay. Once their roots are established and happy, they can be in bloom ten months out of the year. I have a Dendrobium Classic Gem 'BFC' that has already bloomed four times since November. The blooms are long-lasting (but peloric, which I really do not like).

There are quite a few options from The Pleurothallid Alliance that can be in bloom all the time under the right conditions. I am sure that Ecuagenera or Andy of Andy's orchids could recommend some good ones.