Arceuthobium. LORANTHACE^E. 1Q7 



branch, and not between the bud-scales only as in the last. Another variety, with very small 

 fruit, is found on Picea Eiujdmanni in Northern Arizona. 



t- (- Stouter, fjreenisJi-brown : accessory branchlets of fruiting specimens mostly 



leaf-bearing. 



3. A. divaricatum, Engelm. Stouter than the last, 2 to 4 inches high and a 

 line in diameter at base, olive green or pale brownish ; branches spreading, often ttex- 

 uous or recurved : staminate flowers few and scattered or in 3 7 -flowered spikes, a 

 line wide, with ovate acute lobes: fruit 1J to If lines long. PI. Wheeler, 1874, 

 16, and Wheeler's Rep. vi. 253. A. campylopodum, var., Engelm. PL Lindh. 114. 



On Pinus cdulis and P. monophylla, from New Mexico and S. Colorado to Arizona and S. 

 Utah, and to be looked for on the latter species in S. California. Flowering in August and Sep- 

 tember. Intermediate in size and color between A. Douylasii and the following species, but well 

 characterized by its slender habit, spreading growth, and small and rather scanty male dowel's. 



4. A. occidentale, Engelm. Stout, 2 to 5 inches high, 2 to 2 lines thick at 

 base, paniculately much-branched : staminate plants brownish yellow, smaller, the 

 pistillate commonly of a darker olive-brown color : staminate flowers in long dense 

 spikes, often 9 to 17 on a single axis, their buds ventricose with the upper edge 

 curved outward ; calyx 3-5- (usually 4-) parted, 1^ to 2 lines wide ; anthers sessile 

 below the middle of the lanceolate acuminate lobes : fruit 2^ lines long. 



Var. abietinum, Engelm. More spreading and less densely branched, the acces- 

 sory branches in the fruiting plant bearing fertile flowers as often as they do leaf- 

 buds. A. abietinum, Eugelm. Proc. Arner. Acad. viii. 401. 



On various conifers of the Coast Ranges and Sierra Nevada (Pinus insignis, P. Scibiniana, and 

 P. ponderosa), from Salinas Valley and Walker's Basin to Oregon. It is the only American species 

 found also on Junipcrus (Silver Mountain, Brewer). The variety occurs on Abies grandis in 

 the valley of the Columbia, Hall. Flowering in August and September. 



The closely allied A. VAOINATUM, Eichler (Viscinn vaginatum, HBK.), upon the pines of the 

 Mexican mountains, of which only incomplete material has been collected, has shorter spikes and 

 smaller mostly 3-parted staminate flowers with broader and shorter lobes. A. ROBUSTUM, Engelm., 

 on Pinus ponderosa in the Rocky Mountains and Arizona, has shorter spikes than A. occidentale, 

 with shorter flat appressed staminate buds, the 3-parted flowers (opening in June) with shorter 

 and broader lobes, bearing the anthers above their middle. Of the only remaining known species 

 of this curious genus Seemann gathered on the Sierra Madre of Mexico a staminate specimen, in 

 bud only, which is distinguished from all others by its greater thickness and by the long spikes 

 of large verticillate 4-parted flowers, mostly 6 in a whorl. It may therefore bear the name 



A. VERTICILLIFLOUUM. 



