

232 MISC. PUBLICATION 42 3, U. S. DEPT. OF AGRICULTURE 

 1. PHORADENDRON. 32 Mistletoe 



Plants with or without chlorophyll; leaves with well-developed 

 blades or reduced to scales; style short, the stigma usually capitate. 



Key to the species 



1. Leaves reduced to triangular scales not more than 2 mm. long (2). 



2. Stems not crowded, the branches relatively slender, terete, nexuous; leaf 

 scales only slightly connate; spikes often tomentulose, the pistillate ones 

 with 3 or more nodes; berries usually red 1. P. californicum. 



2. Stems crowded, the branches stout, obscurely quadrangular, rather rigid; 



leaf scales strongly connate; pistillate spikes with only 1 node; berries 



whitish 2. P. juniperinum. 



1. Leaves with well-developed blades seldom less than 1 cm. long (3). 



3. Pistillate spikes with more than 2 (usually 6 or more) flowers at each node; 



leaf blades broadly elliptic, ovate, obovate, or nearly orbicular, commonly 



more than 10 mm. wide, distinctly petiolate; spikes more than 5 mm. 



long (4). 



4. Fruits glabrous (the calyx sometimes puberulent), 4 to 5 mm. in greatest 



diameter when mature; herbage glabrous, short-pilose, or subtomen- 



tose; leaf blades commonly more than 3 cm. long. 



6. P. MACROPHYLLUM. 



4. Fruits puberulent at apex (the pubescence not confined to the calyx), about 



3 mm. in greatest diameter when mature; herbage closely puberulent; 



leaf blades rarely more than 3 cm. long 7. P. coryae. 



3. Pistillate spikes with 2 flowers at each node, commonly only 2-flowered; 

 leaf blades linear-spatulate or oblanceolate, not more (usually much 

 less) than 10 mm. wide, sessile or nearly so; spikes in flower not more 

 than 5 mm. long (5). 



5. Stems and leaves tomentulose; leaf blades linear-spatulate, 2 to 3 (seldom 



4) mm. wide, sessile 3. P. bolleanum. 



5. Stems and leaves glabrous; leaf blades oblanceolate (6). 



6. Leaves sessile, 10 to 15 mm. long, seldom more than 4 mm. wide; 



staminate spikes commonly about 1 2-flowered 4. P. densum. 



6. Leaves subpetiolate, 15 to 30 mm. long, 5 to 10 mm. wide; staminate 

 spikes commonly about 8-flowered 5. P. pauciflorum. 



1. Phoradendron californicum Nutt., Acad. Nat. Sci. Phila. Jour. 



ser. 2, 1: 185. 1848. 



Common in the semidesert southern and western parts of the 

 State, 4,000 feet or lower. Southern Utah and Arizona to southern 

 California and northern Mexico. 



Parasitic chiefly on leguminous shrubs and trees (Acacia, Prosopis, 

 Cercidium) , but occasionally on Rhamnaceae. A common form in 

 Arizona is var. distans Trelease, with spikes more elongate and whorls 

 of fruit more widely spaced than in the typical form of the species. 



2. Phoradendron juniperinum Engelm., Amer. Acad. Arts and Sci. 



Mem. ser. 2, 4: 58. 1849. 



Apache, Navajo, and Coconino Counties, south to Cochise and 

 Pima Counties, 4,200 to 7,000 feet. Southwestern Colorado and 

 southern Utah to western Texas, Arizona, and northern Mexico. 



Parasitic on several species of juniper. The plant has yellowish or 

 light brown stems and resembles a large Arceuthobium. 



3. Phoradendron bolleanum (Seem.) Eichler inMart.,Fl.Bras.5 2 :134. 



1868. 

 Coconino County to Cochise, Santa Cruz, and Pima Counties, 

 3,500 to 7,000 feet. Western Texas to Arizona and northern Mexico. 



32 Eeference: Trelease, W. the genus phoradendron, a monographic revision. Urbana, HI., 

 1916. 



