COLORADO TREES 



67 



Juniperus communis Linn. Juniper. 



Sabina scopulorum (Sarg.) Rydb. Cedar. 



Sabina monosperma (Englm.) Rydb. Cedar. 



Sabina utahensls (Englm.) Rydb. Cedar. 



Populus tremuloides Michx. Aspen. 



Populus wislizeni (S. Wats.) Sarg. Cottonwood. 



Papulus sargentii Dode, (P. occidentalis Rydb.) Western Cottonwood. 



Populus acuminata Rydb. Lanceleaf Cottonwood. 



Populus angustifolia James. Narrowliaf Cottonwood. 



Populus balsamifera Linn. Balsam Poplar. 



Salix wrightii Anders. Willow. 



Salix amygdaloides Anders. Peach Willow. 



Salix exigua Nutt. Narrowleaf Willow. 



Salix nuttallii Sarg. Black Willow. 



Salix bebbiana Sarg. Bebb's Willow. 



Betula andrewsii. A. Nels. 



Betula fontinalis Sarg. Canyon Birch. 



Alnus tenuifolia Nutt. Alder. 



Quercus utahensis (A. DC.) Rydb. Oak. 



Quercus leptophylla Rydb. Oak. 



Celtis reticulata Torp. Hackberry. 



Cercocarpus parvifolius Nutt. Mountain Mahogany. 



Crataegus erythropoda Ashe. (C. cerronis Nels.) Thornapple. 



Crataegus Colorado Ashe. Thornapple. 



Crataegus coloradensis Nels. Thornapple. 



Crataegus wheeleri Nels. Thornapple. 



Crataegus saligna Greene. Thornapple. 



Sorbus scopulina Greene. Mountain Ash. 



Prunus americana Marsh. Wild Plum. 



Prunus pennsylvanica Linn. f. Red Cherry. 



Prunus melanocarpa (Nels.) Rybd. Choke Cherry. 



Robinia neo-mexicana Gray. Pink Locust. 



Acer glabrum Torr. Mountain Apple. 



Acer negundo Linn. Box Elder. 



Acer texanum Pax. Box Elder. 



Fraxinus anomala Torr. Ash. 



The above list is probably about complete except for the 

 willows. Many species of Salix which are ordinarily only 

 bushes may at times be truly tree-like. It is thus very difficult 

 to say that any known shrubby species is never a tree. It is 

 hoped that additions to the tree flora of Colorado may be 

 recorded in the "Plant World." — Boulder, Colorado. 



A WATER-STORAGE ORGAN IN CUSCUTA. 



A species of Cuscuta found in Northern Zacatecas, Mexi- 

 co, presents what appears to the writer an unusual structure 

 for this genus, so far as he is able to recall the records. This 

 consists in a bulbous enlargement of the hypocotyl, involv- 

 ing also the radicle. The bulb is short spindle shaped, 4 mm. 

 long with a thickness of 2 mm., the lowest 8 mm. consist- 

 ing of the radicle. It is white, while the upper filiform por- 

 tion of the stem is yellow. The whole of the bulb is normally 

 below the surface of the ground, the radicle and lower part 

 of the bulb producing roothairs. Being translucent, the vas- 



