Oct., 1913-Mar., 1914 Illustrations xv 
A Twig Blight of Quercus Prinus and Related Species—Continued: p ag e 
Fig. 5 .—Diplodia longispora: Types of germination. A, B, Germ tubes 
from end of spore; C, germ tube from side of spore. 344 
6. —Diplodia longispora: A portion of mycelium showing the coalescing 
of the hyphae. 345 
7. —Diplodia longispora: A portion of mycelium with chlamydospore- 
like bodies. 345 
New Potato Weevils from Andean South America: 
Fig, 1 .—Premnotrypes solani Pierce: Lateral view of prothorax and beak. 348 
2. —Premnotrypes solani Pierce: Frontal view of beak. 348 
3. —Trypopremnon latithorax Pierce: Lateral view of thorax and beak. 349 
Indicator Significance of Vegetation in Tooele Valley, Utah: 
Fig. 1.—Curve showing the relation between the salt content (in percent¬ 
ages of the dry weight of the soil) and the specific electrical 
resistance (in ohms) of the soil when saturated with water._ 368 
2. —Monthly distribution of precipitation at Tooele, Utah (mean for 
15 years). 369 
3. —A representative 10-meter quadrat of the sagebrush association, 
showing the location of each individual of Artemisia tridentata 
and of Gutter rezia sarothrae t these being the only woody species 
present.*.. 379 
4. —Artemisia tridentata (sagebrush): A, Detail showing the wedge- 
shaped, 3-toothed leaves by which this plant is easily recog¬ 
nized; B, a small plant growing where hardpan occurred, show¬ 
ing the deflection of the taproot from a vertical to a horizontal 
direction after reaching a depth of 5 inches. 381 
5. —A small plant of sagebrush (Artemisia tridentata ), showing the 
deeply penetrating taproot and good development of superfi¬ 
cial lateral roots typical of this species. 384 
6. —A representative 10-meter quadrat of the Kochi a association, 
showing the location of each tuft of Kochia and of each matlike 
colony of Poa sandbergii . 390 
7. —Kochia vestita: A , Detail showing the narrow, hairy leaves; B, a 
plant showing the shallow root system and the propagation by 
root shoots. 392 
8. —A representative 10-meter quadrat of the shadscale association, 
showing the location of each individual plant of Atriplex con - 
S olia , the only woody species present,, and of Opuntia sp.. 395 
x confertifolia (shadscale): A , A typical plant, showing the 
thick, vertical taproot and the widespreading lateral roots; B, 
detail of a fruiting branch, showing the shape of the leaves and 
of the bracts, or scales, which envelop the fruits. 398 
10 .—Sarcobatus vermiculatus (greasewood): A , Detail showing the nar¬ 
row, rather fleshy leaves; B, a plant showing the excellent root 
development... 404 
11 .—Allenrolfea occidentals: A, Detail of a fruiting branch, showing the 
cylindrical, fleshy, practically leafless stems; B , a plant show¬ 
ing the large taproot and rather scanty lateral roots character¬ 
istic of this species. 409 
12.—A representative 10-meter quadrat of the Allenrolfea community 
(salt-flat association), showing the location of each individual 
plant of Allenrolfea occidentals > the only species present. 410 
13.—Diagram showing the characteristic root development of the dom¬ 
inant species of each of the principal types of vegetation of 
Tooele Valley and indicating the average conditions of soil 
moisture and salinity of the corresponding types of land. 412 
Citropsis, a New Tropical African Genus Allied to Citrus: 
Fig. 1 .—Citropsis Schweinfurthii: A branch showing 3-foliate and 5-foliate 
leaves, leaflike petioles, and rachis segments; also paired and 
single spines in the axils of the leaves. 419 
2 .—Citropsis Schweinfurthii: Young seedlings germinated in Wash¬ 
ington, D. C., from seed from Budongo Forest, Uganda, Africa. 
A, Young seedling, showing the first pair of leaves, succeeded 
by alternate simple leaves, and finally unifoliate leaves; B and 
D, young seedlings, showing the first foliage leaves, which are 
opposite; C, a single one of the pair of first foliage leaves. 422 
