Contributed by MelT

In 2007 my brother sent me an envelope of 11 year old chile seeds that were supposedly from "a wild chile from Peru".  He said that he had seen  it growing in an experimental garden at the University of California at Davis [a major agricultural research center] some time in the early 1990s, and that a researcher who happened to be present had let him collect seeds to grow.  He said he was told that the plants were being grown for chile breeding research. Unfortunately, nothing was written down and nothing more is known. He is pretty sure about the "Peru" part.

I was a bit disappointed that the young plants I grew plainly belonged to the Capsicum annuum/C. frutescens/C. chinense complex and weren't something more exotic,
but it still remained a puzzle. It's a distinctive form that doesn't match the usual "wild chile" forms. It is a low-growing plant, with long-stalked slightly rhomboidal leaves tending to be flattened out together horizontally on spreading branches [hard to see in the photo, but it has a distinctive look]:

A  large plant late in the season, approaching a meter high:

       Flowers and young fruit. Young fruits early develop a swollen receptacle(stalk apex/base of calyx). Unripe fruits exposed to sun become dark.

Although it clearly is a "primitive" chile variety, it isn't like any truly wild chiles of the C. annuum group that I've seen.  Although it probably should be assigned to Capsicum annuum, it's not much like a wild tepin chile. Typical annuum traits: mostly single flowers (a few pairs), with white corolla. It has a different growth habit, lacks the slender wiry twigs of tepins.  Its flower and fruiting stalks are downward-curved or oblique, not upright and erect as in tepins and primitive C. frutescens and  C. chinense. 

Perhaps it's of hybrid origin, or a feral "wild" plant derived from some formerly cultivated C. annuum var. annuum?  Its fruits are hardly "improved" over the tepin type, which
seems problematic for a cultivated origin.  A hybrid origin can't be very recent, since it shows little or no variability from seed.

Ripe fruits are uniform, and separate easily when ripe:

The flesh is thin [full of seeds], hot, and dries easily. The plant and its fruit may not be too exciting, but what makes the plant most interesting to me is its "promiscuous" hybridizing behavior. 
Since it seemed to be closest  to C. annuum,  I of course tried crossing it with different annuum forms:

UC Davis chile X C. annuum v. glabriusculum Tepin (Tarahumara) produced an attractive little F1 plant:

UC Davis chile X C. annuum"Fresno" F1
full-sized unripe fruit.

[Both the above F1 crosses seemed potentially useful hot chiles] Okay, so it crosses freely with C. annuum, both wild and cultivated. One might be tempted to see that as strong evidence of its species identity.  

That would be misleading, because as it turns out this plant also hybridizes just as freely with basically every other chile I've tried crossing it with, producing in each case what appear to be fully fertile F1 hybrids.  It seems a remarkably willing hybridizer, both as seed parent and pollen parent.  (However, I must admit that I really haven't made comparable efforts with other varieties, so maybe it's not really that unusual). Anyway, the crossing behavior of this plant might make a person despair for the validity of
the C. annuum/C. frutescens/C. chinense species distinctions. Crossing it with C. frutescens "Duke Pequin" [no image], produced an erect very
frutescens-like plant with lots of tiny red berries.

Crosses with C. chinense include:
UC Davis chile X C. chinense "Wild Brazil" F1

UC Davis chile X C. chinense Bhut Jolokia F1 fruit on a low-growing
spreading plant

full-sized unripe fruit

Also crossed  it with C. chinense "Marawiri", making another colorful C. chinense-like hybrid.A few additional crosses in 2009, including ones with C. chacoense "Cobincho" and 
C. baccatum "Lemon Drop" also produced seeds.  I'll see if they grow.