KEY TO THE GENERA OF TREES IN THE 

 SUMMER CONDITION. 



Based mainly on leaf and twig characters. Ihv nnnilier 

 following the generic name refers to the list nuniher. 

 1. i'^oliage leaves witli expanded hlades, netted-veined. ("<. 

 I. P'oliage lea\es needle-sliai)ed. narrow! \- linear, snl)- 

 nlate. or scale-like; conifers. "_'. 



1. P'oliage leaves fan-shaped with dichotomous venation. 



a numher on thick, wart-like, persistent dwarf 

 branches. Ginkgo. (1). 

 "2. With typical dwarf hranclies. ])ersistent for more than 

 1 year. •?. 



2. With feather-like dwarf ])ranclies. deciduous each 



year, the linear leaves spreading into 2 ranks. 



Taxodium. cJ). 



2. Without dwarf hranches. 4. 



■'I. Dwarf l)ranche> small. self-])rune(l. with 2-^) foliage 

 leaves. Pinus. (7). 



•".. Dwarf hranches thick, wart-like, persistent, with nu- 

 merous deciduous leaves. Larix. ((5). 



i. Leaf huds scaly: leaves scattered. •'). 



I. Leaf buds not scaly, naked: leaves opposite or 

 whorled. 7. 



•"). Leaf scar on a sterigma. the twigs covered with scales 

 representing the leaf bases. •!. 



•'i. Leaf scar on the hark: twigs without scales: leaves 

 llat. Abies. (•")). 



<!. Leaves Ihil, lluise on the ui»per side of the lwi>4 much 

 shorter tliaii the lateral ones; trees. Tsuga. (4). 



li. Leaves more or less 4-side(l, si)rcading in all direc- 

 tions. Picea. (:'.). 



7. h'oliage leaves small, scale-like, appressed. opposite 

 1-ranked. closely covering the twigs which are de- 

 cidedly llattened and fan-like: leaves of two shapes, 

 the dorsal and ventral broa(K*r and less acute than 

 the lateral (Mies; scales of the carpellate cone <»-In. 

 not ]>el(:ite Thuja. (S). 



(11) 



