Family Papilionatae:
The family Papilionatae, also known as the Fabaceae or Leguminosae family, is a large family of flowering plants. This family is known for its economic importance as it includes many species that are used for various purposes, including food. One of the main reasons why this family is considered to yield "poor man's protein" is because of the high protein content found in its seeds.

High Protein Content:
The seeds of plants belonging to the family Papilionatae are rich in protein. This makes them a valuable source of nutrition for those who cannot afford more expensive sources of protein. Protein is an essential macronutrient that is required for growth, repair, and maintenance of the body. It plays a crucial role in the development of muscles, tissues, enzymes, and hormones.

Legumes:
The family Papilionatae includes leguminous plants, which are known for their ability to fix nitrogen in the soil. Legumes have a unique symbiotic relationship with nitrogen-fixing bacteria, which allows them to convert atmospheric nitrogen into a form that can be used by plants. This nitrogen fixation process enriches the soil with nitrogen, making it more fertile for other plants to grow. This is one of the reasons why legumes are often used as cover crops or in crop rotation systems.

Variety of Species:
The family Papilionatae is incredibly diverse and includes numerous species, each with its own unique characteristics and uses. Some examples of leguminous plants include soybeans, lentils, chickpeas, peas, and peanuts. These plants are cultivated worldwide and are consumed in various forms, such as whole seeds, flours, oils, and as ingredients in various dishes.

Other Nutritional Benefits:
In addition to their high protein content, legumes also offer other nutritional benefits. They are a good source of dietary fiber, vitamins (such as folate and vitamin B6), minerals (such as iron and magnesium), and antioxidants. Including legumes in the diet can help improve digestion, regulate blood sugar levels, lower cholesterol, and support overall health.

Conclusion:
The family Papilionatae, or Leguminosae, is known for yielding "poor man's protein" due to the high protein content found in its seeds. Leguminous plants are not only rich in protein but also offer other nutritional benefits. They are widely cultivated and consumed worldwide, providing a valuable source of nutrition for many people, especially those who cannot afford more expensive sources of protein.