Cos is not a pear. It is a type of lettuce, also called romaine lettuce.
Cos
Pyrus communis is commonly known as the European pear or common pear. It is native to central and eastern Europe and southwest Asia. In the U.S. 1% of commercial pear production is from the Doyenne du Comice (France 1849) which is commonly just called Comice pears.
A Bartlett is a pear
A large 166g comice pear = 100 calories. Therefore every 100g of pear = 60 calories. So if you know exactly how large it is you can do the maths. :)
The correct spelling is Bartlett pear, or Williams pear, the US name coming from grower Enoch Bartlett.
apple green
comice are grown in the same way as any other european pear, they hang a bit longer on the tree until maturity than anjou and several picks will yield a larger piece of fruit.
grafting
Ubileen can successfully cross pollinate with Orcas, Seckel, Highland, Comice, Bosc and Asian Pears.
Bartlett usually refers to a variety of a pear with yellowish skin and soft, juicy white flesh.
Mid April
Pear
Angiosperm By Wesley W. SIsk