Dr M continues his focus on Poaceae with a look into the Tribes of grasses. In his legendary Poaceae song Dr M has already established that the Poaceae is a family of grasses green and wonderful! But notwithstanding this fact, the beginning and even the intermediate botanist often needs some guidance and tips for sorting the genera and species into a framework to help identify common species and to go on to identify unfamiliar grasses.
Dr M is a big fan of the BSBI guide to grasses by Tom Cope and Alan Gray (2009), and in this book the authors start their journey through the Poaceae by focusing on the tribes of grasses. This approach has the advantage of dividing the larger total into smaller more manageable units based on key characters. Once the correct tribe is identified then you can continue to separate the different genera within the tribe and ultimately the different species within the genus. Cope & Gray’s work built on the approach adopted earlier in the seminal volume Genera Graminum by Clayton and Renvoize (1986).
Globally there are approximately 800 genera of grasses (and 10 000 species) and these can be grouped into 28 tribes. This is a big undertaking and fortunately in Britain we have fewer grasses to get to grips with! Actually this makes Britain a very good place to start a journey through the Poaceae!
So, looking at Cope & Gray’s book, thirty-two of the fifty Native British genera of grasses can be placed in just 2 tribes – the Poeae and the Aveneae. The remaining 18 genera can be placed in a further 8 tribes.
The key questions then are: which genera occur in the Poeae and the Aveneae and what are the key characters that distinguish these two tribes? Check the links to find out!
July 17, 2013
