STANDLEY TREES AND SHRUBS OF MEXICO. 226 



Leaves more or less spatulate. 



Leaves spatulate-liiiear 31. P. bolleanum. 



Leaves oblanceolate-spatulate. 



Spikes usually 2-jointe(l ; staminate spikes mostly 6-flo\vereil. 



32. P. guadalupense. 

 Spikes usually l-joiuted ; staminate spikes 8 to 12-flowered. 

 Stamiuate spikes about 12-flo\vered ; on Juniperus. 



33. P. densum. 

 Staminate spikes about 8-flowered; on Ahies and Gupresstis. 



34. P. pauciflorum. 

 Pistillate flowers 6 or more on each joint. 

 Branches compressed at the joints. 



Leaves 10 to 25 mm. wide 35. P. scaberrimum. 



Leaves 5 to 7 mm. wide 36. P. longifolium. 



Branches not compressed. 



Leaves mostly acute or attenuate, large (mostly 7 to 10 cm. long), 



pubescent 37. P. velutinum. 



Leaves rounded or very obtuse ;it the apex, or if acute very small. 

 Leaves small, usually 1 cm. wide or less, if larger very long in pro- 

 portion to their breadth. 



Plants pei'sistently tomentose 38. P. lanatum. 



Plants not persistejitly tomentose, the pubescence sparse or soon 

 deciduous. 

 Fruit villous or hispid. 



Leaves oval or elliptic 39. P. eduardi. 



Leaves linear-oblanceolate to narrowly oblong. 



Fruit retrorsely hispid. Sepals closed 40. P. galeottii. 



Fruit sparsely villous. 



Sepals closed 41. P. peninsulare. 



Sepals open 42. P. palmeri. 



Fruit glabrous or puberulent. 



Leaves subacute, sessile 43. P. mazatlanum. 



Leaves very obtuse, usually petiolate. 

 Plants large, stout. 



Leaves sessile 44. P. globuliferum. 



Leaves petiolate. 



Plants glabrate 45. P. brachystachyum. 



Plants densely pubescent throughout. 



46. P. tlacolulense. 

 Plants small (of Baja California). 



Leaves oval or rounded 47. P. aureum. 



Leaves oblong or obovate-oblong 48. P. diguetii. 



Leaves large, most of them 2 cm. wide or larger, never nmch elongate. 

 Fruit pubescent. 



Leaf blades mostly 5 to 8 cm. long 49. P. robinsoni. 



Leaf blades usually less than 4 cm, long. 



Leaves orbicular or nearly so 50. P. coryae. 



Leaves elliptic or obovate 51. P. tomentosum. 



Fruit glabrous. 



Spikes yellow-hispid 52. P. colipense. 



Spikes glabrous, tomentose, or sparsely villous. 

 Spikes glabrous or sparsely villous. 



Leaves suborbicular 53. P. macrophyllum. 



Leaves rounded-obovate 54. P. cockerellii. 



