BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Hesperostipa spartea | Porcupine Grass 



GENERAL BOTANICAL CHARACTERISTICS : 
Porcupine grass is a native, perennial, cool-season bunchgrass.  It is
often confused with needle-and-thread grass, but its leaves are longer,
generally less rolled, lighter in color, and considerably wider [18].
It may grow to a height of 4 feet (1.2 m) but generally reaches 1.5 to 3
feet (0.45-0.9 m).  Flower stalks grow from 2 to 4 feet (0.6-1.2 m).
Root systems of mature plants usually reach depths of about 4.5 feet
(1.35 m), but occasionaly extend to 6 feet (1.8 m).  Numerous, profusely
branched, smaller roots occupy the top 8 to 18 inches (20-46 cm) of
soil, spreading horizontally or diagonally downward.  The longer roots
give rise to many laterals which divide into fine branches in deeper
soil [47].



RAUNKIAER LIFE FORM : 
   Undisturbed State:  Cryptophyte (geophyte)
   Burned or Clipped State:  Cryptophyte (geophyte)


REGENERATION PROCESSES : 
Porcupine grass reproduces sexually [12].  The seeds have a unique
method of planting themselves.  As the twisted awns expand and contract
with variations in temperature and moisture, the seeds are drilled into
the soil.

Strong winds may transport seeds a considerable distance, especially
when awns are twisted together in clumps [42].  Animals also carry seeds
as the awns become trapped in their coats.


SITE CHARACTERISTICS : 
Porcupine grass is found in prairies, foothills, and canyons at lower
elevations, often dominating dry, well-drained sites [14,45].  In
Colorado it is found from 5,300 to 7,500 feet (1,615 to 2,286 m) in dry
to moist habitats [12].  In Minnesota it is dominant on a sandy level
upland.  It also occurs on well-drained gentle slopes but is not
dominant [13].  In Nebraska it is found on high prairie, low prairie,
and disturbed areas, but is typically an upland species, generally
dominant on south and east slopes [8,42].  It mainly occurs on poorer
soil types throughout the northern Great Plains [40].


SUCCESSIONAL STATUS : 
Porcupine grass is a climax dominant on several sites in the Great
Plains [8,28,45].  It also occurs as a pioneer species, often
establishing on small disturbed or denuded areas, such as gopher mounds
[42].


SEASONAL DEVELOPMENT : 
Leaf growth of porcupine grass begins in late March to early April in
western North Dakota [18].  Flowering occurs earliest in the eastern and
southern, and latest in the northern and western portion of its range
[33].  In Wyoming, North Dakota, and Nebraska flowering occurs from May
to June [12,42], and in Montana from June to August [12].

A study in western North Dakota recorded an 8-year average of the
significant phenological stages of porcupine grass [18].

Initiation of   Head                  Seed       Seed      Leaves
Fruiting Stalk  Emergence  Anthesis   Maturity   Shatter   50-75% Dry

June 2          June 14    June 28    June 27    July 9    August 28
    

Related categories for Species: Hesperostipa spartea | Porcupine Grass