106 LORANTHACE.E. Arceuthobium. 



2. ARCEUTHOBIUM, Bieb. 



Flowers axillary and terminal, solitary or several from the same axil. Staminate 

 flowers 2-5- (mostly 3-) parted, compressed or the terminal ones globose before 

 opening. Anthers adnate to the lobes, circular and 1 -celled, dehiscing by a circidar 

 slit at base ; pollen-grains spinulose. Pistillate flowers ovate, compressed, 2-toothed, 

 subsessile and partly enclosed ; the pedicel at length elongated, exsert and recurved. 

 Berry fleshy, compressed, dehiscent at the circumscissile base. Cotyledons very 

 short, only indicated by a notch. Parasitic on conifers, glabrous, with rectangular 

 branches and connate scale-like leaves : flowers often crowded into apparent spikes 

 or panicles, opening (in our species) in summer or autumn and maturing their fruit 

 in the second autumn, when the berries suddenly and forcibly eject the glutinous 

 seeds to the distance of several yards. 



A small genus, represented in S. Europe by a single species, and in America ranging from the 

 northern border of the United States to Mexico, chiefly in the mountains. 



* Staminate flowers all (or nearly all) terminal on distinct peduncle-like joints, 



paniculate. 



1. A. Ameiicanum, Nutt. Slender, dichotomously or verticillately much- 

 branched, greenish yellow ; staminate plants sometimes 3 or 4 inches long (| to a 

 line thick at base), fertile plants much smaller : flowers small, the staminate a line 

 broad or more, with ovate-orbicular acutish lobes, the pistillate a half to one line 

 long : fruit 2 lines long. Engehn. PI. Lindh. 214, and Wheeler's Rep, vi. 252. 



Only on Pinus contorta (and apparently P. Banksmim in the Saskatchewan region), from 

 Wyoming to Oregon and southward to Colorado and California (Little Yosemite Valley, 

 Bolcmder). Flowering mostly late in autumn apparently, but found by Parry in Wyoming in 

 flower in July ; fruit mature in August and September. Its shoots creep along within the tissue 

 of the bark on young branches of the pine, and in the autumn bud out in the form of little knobs 

 among the bud-scales at the end of three-years-old limbs, developing into flowering plants the 

 next season. When once established it may continue to sprout from the same base for many (30 

 or more) years, causing hypertrophy of the wood and bark of the limb and often its final destruc- 

 tion. Fruiting and flowering branchlets are often seen in juxtaposition in the same whorl, but 

 without leaf-bearing branchlets, and never in superposition. 



The type of the genus, A. Oxyccdri, Bieb., of the Old World, is allied to this, but distinguished 

 from it and from all American species by its staminate flowers being all terminal on short branch- 

 lets and usually in threes, scarcely a line wide and with orbicular lobes, and by the much smaller 

 oblong fruit, less than 1 lines long. The northeastern A. jmsillum, Peck, of the Adirondacs, 

 growing on Picca nigra, also belongs to this section. 



* * Staminate flowers axillary (with a terminal one), forming simple or com- 



pound spikes. 



t Slender, greenish-yellow: accessory branchlets of fruiting specimens flower- 

 bearing. 



2. A. Douglasii, Engelm. Similar to the last, but smaller, \ to 1 inch high : 

 branches suberect, solitary, or with accessory ones behind (never beside) the primary 

 ones : flowers in short (usually 5-flowered) spikes ; the staminate less than a line 

 wide with orbicular-ovate acutish lobes : fruit 2A lines long. Wheeler's Rep. 

 vi. 253. 



Var. abietinum, Engelm. A larger form, 1 to 3 inches high (the fertile smaller) 

 with spreading or even recurved few- flowered branchlets : staminate flowers 1 \ lines 

 wide : fruit scarcely 2 lines long. 



On Pscudotsuga Douglasii, from New Mexico to S. Utah and N. Arizona ; the variety on Abies 

 concolor in Sierra Valley (J. G. Lenmion) and S. Utah, Parry. Flowering apparently in October. 

 Distinguished from the last by its usually smaller size, the superimposed (never verticillate) ac- 

 cessory branchlets, lateral flowers, and larger fruit. Its creeping stroma buds out all along the 



