Alongside numerous wild varieties, there are a wide range of cultivated (chili) peppers. Capsicum annum, which is most commonly used, is available in varieties ranging from a mild bell pepper to a hot pepper and in sizes from barely pea-sized to up to 25 cm long — and also comes in a wide range of colors and shapes.
From Wikipedia: “Capsicum /ˈkæpsᵻkəm/ (also known as peppers) is a genus of flowering plants in the nightshade family Solanaceae. Its species are native to the Americas, where they have been cultivated for thousands of years.
Following the Columbian Exchange, it has become cultivated worldwide, and it has also become a key element in many cuisines. In addition to use as spices and food vegetables, Capsicum species have also been used as medicines and lachrymatory agents.”
Etymology and names:
“The generic name may come from Latin capsa 'box', presumably alluding to the pods or the Greek word κάπτω kapto 'to gulp'. The name "pepper" comes from the similarity of the flavor to black pepper, Pipernigrum, although there is no botanical relationship with it or with Sichuan pepper. The original term, chilli (now chile in Mexico) came from the Nahuatl word chilli, denoting a larger Capsicum variety cultivated at least since 3000 BC, as evidenced by remains found in pottery from Puebla and Oaxaca.
The fruit of Capsicum plants have a variety of names depending on place and type. The piquant (spicy) varieties are commonly called chili peppers, or simply "chillies". The large, mild form is called red pepper, green pepper, or bell pepper in North America and United Kingdom and typically "capsicum" in New Zealand, Australia, Singapore and India. The fruit is called paprika in some other countries (although paprika can also refer to the powdered spice made from various capsicum fruit).”
Species and varieties:
“Capsicum consists of 20–27 species, five of which are domesticated: C. annuum, C. baccatum, C. chinense, C. frutescens, and C. pubescens. ...
Many varieties of the same species can be used in many different ways; for example, C. annuum includes the "bell pepper" variety, which is sold in both its immature green state and its red, yellow, or orange ripe state. This same species has other varieties, as well, such as the Anaheim chiles often used for stuffing, the dried ancho (also sometimes referred to as poblano) chile used to make chili powder, the mild-to-hot jalapeño, and the smoked, ripe jalapeño, known as chipotle.”
“Most of the capsaicin in a pungent (hot) pepper is concentrated in blisters on the epidermis of the interior ribs (septa) that divide the chambers, or locules, of the fruit to which the seeds are attached ...
The amount of capsaicin in hot peppers varies significantly among varieties, and is measured in Scoville heat units (SHU). The world's current hottest known pepper as rated in SHU is the 'Carolina Reaper,' which had been measured at over 2,200,000 SHU.”
“Peppers are incredibly nutritious. They have more Vitamin C than an orange, and a typical bell pepper contains more than 100% of the daily recommended value for Vitamin C. They also have relatively high amounts of Vitamin B6. Fresh fruit is 94% water. Dried pepper fruit has a much different nutritional value due to the dehydration and concentration of vitamins and minerals.”