Distinguish between Spike and Raceme
Spike and raceme are two types of inflorescences found in plants. The main difference between them is the arrangement of flowers along the stem.
1. Spike: A spike inflorescence is a type of flowering structure where flowers are arranged along a single stem. The flowers are sessile, which means they are directly attached to the stem without any stalk. Spikes are usually unbranched and have flowers that are closely spaced without any apparent leaf-like structures between them. Examples of plants with spike inflorescences include wheat, barley, and rye.
2. Raceme: A raceme inflorescence is also a type of flowering structure where flowers are arranged along a single stem. However, unlike a spike, the flowers in a raceme have short stalks or pedicels that allow them to spread out along the stem and give the inflorescence a more open appearance. The flowers in a raceme are usually arranged in a single row along the stem and are often accompanied by small leaf-like structures called bracts. Examples of plants with raceme inflorescences include grapes, lupines, and sweet peas.
To distinguish between a spike and a raceme, we need to understand their botanical definitions and characteristics.
1. Spike:
- A spike is an inflorescence where the flowers are sessile, meaning they do not have individual stalks (pedicels).
- The flowers are directly attached to the main stem or rachis.
- The arrangement of flowers is usually unbranched and elongated.
- The flowers on a spike are typically arranged closely together along the main stem or rachis.
- Examples of plants with spikes include wheat, rye, barley, and catkins of birch trees.
2. Raceme:
- A raceme is an inflorescence where the flowers are pedicellate, meaning they have individual stalks (pedicels).
- The flowers are attached to the main stem or rachis by their pedicels.
- The arrangement of flowers is usually unbranched and elongated.
- The flowers on a raceme are typically spaced out along the main stem or rachis.
- Examples of plants with racemes include grapes, lupines, lilies, and delphiniums.
In summary, the main difference between a spike and a raceme lies in the way the flowers are attached to the main stem or rachis. In a spike, the flowers are directly attached, while in a raceme, the flowers have individual stalks.