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Rubus

life science Maturity 5-7 Next article →

Rubus is a massive and highly diverse genus of flowering plants.

Blackberry flower 01
Blackberry flower 01

These plants belong to the Rosaceae family, which is the rose family. Most people know them by the common name brambles. The genus includes many familiar fruits like raspberries, blackberries, and dewberries. Some species also produce bristleberries. Scientists estimate there are between 250 and over 1,000 different species.

Rubus idaeus leaf
Rubus idaeus leaf

These plants are found on every continent except Antarctica. Because they are so varied, they are a major subject of study for botanists.

Most Rubus plants grow as shrubs, though a few are herbaceous. Their stems are typically woody and covered in sharp prickles. Some species use spines, bristles, or gland-tipped hairs for protection.

Aculi
Aculi

These stems are often called canes. Many species are biennial, meaning the shoots do not flower or set fruit until their second year. However, the main rootstock is perennial and stays in the ground. The plants have a unique way of spreading through long, arching shoots. When these shoots touch the soil, they readily grow new roots. This allows the plant to form a large rootstock from which new shoots emerge each spring.

The fruit of a Rubus plant is biologically unique. It is known as an aggregate fruit.

Rubus caesius fruit - Keila
Rubus caesius fruit - Keila

This means the fruit is actually a collection of many smaller units called drupelets. Most Rubus flowers are hermaphrodites. This term means a single flower contains both male and female reproductive parts. Genetic complexity is also very high in this genus. About 60% to 70% of species are polyploid. Polyploidy means they have more than two copies of each chromosome. Species range from diploid, with 14 chromosomes, to tetradecaploid, which has 14 times the standard amount.

Classifying Rubus is one of the greatest challenges in systematic botany.

The genus is extremely complex due to hybridization and polyploidy. It also features facultative apomixis, which affects how they reproduce. Between 1910 and 1914, a German botanist named Wilhelm Olbers Focke attempted to organize the genus. He proposed 12 subgenera, a system that became widely accepted for a long time. However, modern genetic studies have shown that many of these subgenera are not monophyletic. This means they do not all share a single common ancestor. Today, researchers recognize 13 subgenera, with the largest being the subgenus Rubus.

Evidence from fossils helps us understand the history of these plants.

Rubus arcticus3
Rubus arcticus3

The genus likely originated in North America. Fossils from the Eocene-aged Florissant Formation in Colorado are about 34 million years old. During the Miocene epoch, Rubus expanded into Eurasia, South America, and Oceania. Fossil seeds from the early Miocene have been found in the Zittau Basin in the Czech Republic. Other fossil fruits, such as †Rubus laticostatus, were found in the West Carpathians of Poland. These discoveries show how the genus moved across the globe over millions of years.

There are many notable examples of Rubus species across different climates.

Rubus spectabilis 2566
Rubus spectabilis 2566

Some are adapted to the cold, such as the Arctic raspberry, Rubus arcticus. Others thrive in different environments, like the Hawaiian species, Rubus hawaiensis.

Starr 030419-0035 Rubus hawaiensis
Starr 030419-0035 Rubus hawaiensis

You might find the cloudberry, Rubus chamaemorus, in specific habitats.

Rubus chamaemorus fruit
Rubus chamaemorus fruit

Many species are also grown commercially as cane fruits. This includes hybrids like the loganberry, boysenberry, marionberry, and tayberry. These are grown using supports like wires to help the canes grow.

Understanding Rubus connects us to many scientific fields. It links botany to genetics through the study of polyploidy and chromosomes. It also connects to paleobotany through the study of ancient fossils.

Thimbleberry flower (Rubus parviflorus)
Thimbleberry flower (Rubus parviflorus)

The way these plants hybridize provides a look into how new species form. Because they are found in so many different places, they also help scientists study how plants adapt to different environments. From the snowy Arctic to tropical islands, Rubus shows the incredible flexibility of life on Earth.

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🖼️ Images & Media (18)
File:Rubus caesius fruit - Keila.jpg
Rubus caesius fruit - Keila.jpg
File:Rubus arcticus3.jpg
Rubus arcticus3.jpg
File:Rubus-odoratus-flower2.JPG
Rubus-odoratus-flower2.JPG
File:Rubus saxatilis02.jpg
Rubus saxatilis02.jpg
File:Rubus ellipticus obcordatus 3.jpg
Rubus ellipticus obcordatus 3.jpg
File:Aculi.jpg
Aculi.jpg
File:Rubus chamaemorus fruit.jpg
Rubus chamaemorus fruit.jpg
File:Brombeerlaub.jpg
Brombeerlaub.jpg
File:Thimbleberry flower (Rubus parviflorus).jpg
Thimbleberry flower (Rubus parviflorus).jpg
File:Rubus idaeus leaf.JPG
Rubus idaeus leaf.JPG
File:Blackberry flower 01.jpg
Blackberry flower 01.jpg
File:Björnbär.jpg
Björnbär.jpg

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