Heterosis or hybrid vigor is a well-known phenomenon in plant breeding and has been taken advantage of by orchid hybridizers for the last century and a half. The first man-made orchid hybrid registered at the Royal Horticultural Society in 1856 was, in fact, a primary hybrid between Calanthe sylvatica and Calanthe triplicata, creating Calanthe Dominyi. Primary hybrids are special because both parents are 'pure' species, and are often as just as easily identified as their species parents because they exhibit highly consistent morphologies.
Natural primary hybrids are also found in nature between species (often within the same genus) that have had the chance to meet in the wild. These are usually denoted by taxonomists with the x symbol before the species name. Two famous examples of natural primary hybrids in Phalaenopsis are Phalaenopsis x intermedia (Phal. equestris x Phal. sanderiana) and Phalaenopsis x gersenii (Phal. sumatrana x Phal. violacea).
In the case of the genus Phalaenopsis, assuming the currently accepted 64 extant species, there are theoretically 4032 possible primary combinations! Here are but two examples of them -- Phalaenopsis Guadalupe Pineda (Phal. bellina x Phal. amboinensis) and Phalaenopsis Tzu Chiang Tetralitz (Phal. micholitzii x Phal. tetraspis). The Guadalupe Pineda is fragrant, but presents more of the musky scent from Phal. amboinensis rather than the sweeter, fruitier scent from Phal. bellina. Fragrance is also present in Phal. Tzu Chiang Tetralitz, and it can described as being a light, sweet, grassy scent inherited Phal. tetraspis, which also imparts the random pigmented barring on the sepals and petals. Both hybrids will flower more than once a year, which is an additional advantage of having genomes from two species.
Phalaenopsis Guadalupe Pineda (Phal. bellina x Phal. amboinensis)
Phalaenopsis Tzu Chiang Tetralitz 'Little Hearts' (Phal. micholitzii x Phal. tetraspis)