Black pearl, more specifically called black pearl pepper, is a plant of the same family as red peppers.  The fruit turns black and looks like a black pearl, so it must have been named black pearl.  However, the leaves are also black as shown in the photo.  The leaves are green when young, but gradually turn black.  Purple flowers bloom between the black leaves, and eventually purple fruits are produced, and the fruits change from purple to black-purple to red.  Although it is a member of the capsicum, it is only for ornamental purposes and cannot be eaten.  By this time of autumn, colorful fruits such as red, yellow, orange, black, and purple are formed between the black leaves, which is very beautiful.  It is native to the tropics of South and North America and is also known as the onyx red.  Onyx means a black gem, and you may have taken notice of that the fruit changes from black to red.

ブラックパール、詳しくはブラックパールペッパーと言い、唐辛子と同じ仲間の植物です。実が黒くなって黒真珠の様になるからブラックパールと言う名が付いたのでしょう。しかし写真の様に葉も真っ黒です。葉は若葉の時は緑色ですが徐々に黒色に変化します。その黒葉に紫色の花が咲き、やがて紫色の実ができ、その実は紫から黒紫、そして赤へと変化します。トウガラシの仲間ですが、あくまでも観賞専門で食用にはできません。秋の今頃には赤、黄色、オレンジ、黒、紫などカラフルな色合いの実が、真っ黒な葉の間にできて、とても美しいです。南アメリカから北アメリカの熱帯地域が原産で、この地域ではオニキスレッドともよびます。オニキスとは黒い宝石のことで、実が黒色から赤色に変化する事に注目したのでしょう。