BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Vulpia octoflora | Sixweeks Fescue 



GENERAL BOTANICAL CHARACTERISTICS : 
Sixweeks fescue is a small, loosely tufted or solitary, cool-season,
native annual [17,25].  Culms grow from 2 to 8 inches (0.5-2 cm) in
height and are often geniculate at the lower nodes, although otherwise
erect [4].  Blades are narrow, involute, and sparingly pubescent [25].
Branches are short, appressed, or spreading [11].  Laterally compressed,
glabrous, scabrous, or pubescent spikelets are densely flowered (5-17
flowers) [4,25].  Unequal, lanceolate to subulate linear glumes taper
into short awns [4].  


RAUNKIAER LIFE FORM : 
   Therophyte


REGENERATION PROCESSES : 
Sixweeks fescue reproduces by seed which drops to the ground at
maturity.  This winter annual germinates and begins growth during the
fall [14].

Seasonal variations in the density of germinable seeds in a big
sagebrush community have been recorded.  At a Nevada site, sixweeks
fescue was the only native annual to have abundant reproductive reserves
in the litter and soil.  Germinable seed density by microsite was as
follows [27]:

                     Under Shrubs               Between Shrubs
                 Sept.     Nov.     Feb.     Sept.    Nov.    Feb.
                       (seeds/m2)                  (seeds/m2)

Litter          5,350      900      ---      4,350    900     200
Soil              250       50      200      1,200    300     ---

                         Total for Whole Community
                         Sept.     Nov.      Feb.
                                 (seeds/m2)

                         7,130      1,130     200

Germinable seed was most abundant during September and November; no
germinable seed was found in May.  Maximum seedling establishment
occurred in December; establishment decreased by the spring.  All
establishment on this Nevada site was between shrubs rather than beneath
them [27].

The abundance of sixweeks fescue is largely determined by the amount of
precipitation received during the preceding spring.  Ample spring
precipitation favors good growth and seed production [14].  Adequate
fall moisture is also required for good fall germination and stand
establishment [14].  Because of the early phenological development of
sixweeks fescue, summer rainfall is relatively unimportant for good
germination and growth [16].

Light, abundant seed is often dispersed by high winds [26].  Small
mammals could also conceivably aid in seed dispersal.  In Washington
steppe communities, dense, even-aged and short-lived tufts of sixweeks
fescue seedlings approximately 0.8 inch (2 cm) in diameter are sometimes
found in the spring and are presumed to have developed from mouse caches
[5].


SITE CHARACTERISTICS : 
Sixweeks fescue grows well on a variety of open, disturbed areas but is
generally most common on upland range sites [14,25].  It grows best on
sandy or loamy soails [6].  Annual abundance fluctuates greatly
according to the amount of precipitation received [14].

Elevational ranges of sixweeks fescue are as follows [6,14]:

      from:    3,600 to 8,500 feet (1,098-2,600 m)  in CO
               5,000 to 5,000 feet (1,525-1,525 m) in MT
               2,000 to 5,000 feet (610-1,525 m) in UT
               4,000 to 6,100 feet (1,220-1,861 m) in WY



SUCCESSIONAL STATUS : 
Facultative Seral Species

Sixweeks fescue is abundant in disturbed areas but is much less common
or even absent in climax communities.  On disturbed Washington steppe
sites, sixweeks fescue and cheatgrass (Bromus tectorum) increased as
perennial grasses declined [5].  In an Arizona study, sixweeks fescue
increased dramatically following disturbance in the Upper Sonoran Desert
but began to decline within the next several years [2].  Sixweeks fescue
was reported to be a seral dominant during a severe drought period in
the Southwest [26].


SEASONAL DEVELOPMENT : 
Seeds germinate during the fall [14].  Plants emerge in the fall but
growth usually begins in the early spring [14,25].  Sixweeks fescue
grows very rapidly and can mature as early as 6 weeks after the onset of
spring growth [25].  The leaves turn brown rapidly [17].  Generalized
flowering dates are as follows [6]:

       State       Beginning of Flowering       End of Flowering

        CO                May                        June
        MT                March                      June
        WY                May                        June

Seed generally ripens in July [26] and remains abundant in the litter
and soil during much of the year.  In Nevada, germinable seeds of
sixweeks fescue were abundant from September through November, but no
reserves were found in May [27].  Maximum seedling establishment
occurred in December, with a reduction in populations by spring [27].

Related categories for Species: Vulpia octoflora | Sixweeks Fescue