PLATE XXII. 



A, PlXDS KClllN'ATA. Cross sectiou of two nugs; sp. w., springwood; «u. u., summerwood. 



It, PiNUS I'ALUSTRis. Cross section of a very uarrow ring. Of the two mednllary rays one is out tlirongh a row »{ 



parenchyma, the othir through a row of trachcids. 

 C an<l J), PlNl"8 ULABiiA. Kadial sei-tions; m. r., iin-(lul!ary rays; tr., tracheids ol' tlie iiii'ilullary rays; p., parenchyma 

 of thr same; i- }>■, simple pits leading from the parenchyma to the neighboring tracheids or common filn-rs 

 c. Ir.; b. p., bordered pit. The lay at <' is maile up of tracheids only. 

 A', Pixrs I'AHSTitis. Had ial section; lettering as in 1). 



Ori'rinali magnified : A, ^';^, the rest ^f ; illustrations: A, ij', the rest ^2"- 

 U6 



