2. Calamagrostis porteri A. Gray ssp. insperata
(Swallen) C.W. Greene (Ofer Hollow reedgrass)
Pl. 133
a–d; Map 540
C. insperata Swallen
Plants forming loose colonies of scattered tufts. Flowering
stems 25–100(–120) cm long. Leaf sheaths glabrous or less commonly with a line
or band of minute, appressed hairs at the tip, the ligule 3–8 mm long. Leaf
blades 3–40 cm long, 3–12 mm wide, flat, bluish green, glaucous on both
surfaces. Inflorescences 10–30 cm long, open to dense, but not spikelike, the
branches ascending at maturity, the longest branches more than 2 cm long.
Glumes 3.5–6.0 mm long, elliptic‑lanceolate, tapered to a sharp point at
the tip, roughened along the midnerve. Floret with the basal tuft of hairs
about 1/2 as long as the lemma. Lemma 3.0–4.5 mm long, narrowly ovate, the awn
attached toward the base of the midnerve, abruptly twisted and bent near the
middle. 2n=56. July–September.
Scattered in the Ozark Division (Ohio, Indiana, Kentucky, Illinois, Missouri, and Arkansas). Shaded ledges and tops of bluffs with mesic
upland forests, usually on acidic substrates, often on north‑facing
exposures.
Van Schaack (1954) and Steyermark (1963) cited only two
1930s specimens from Douglas and Ozark Counties to support the inclusion of
this taxon in Missouri (a third specimen from Texas County went unnoticed at
the time). Periodic searches by a number of botanists failed to relocate these
plants in nature, and the taxon was presumed to have become restricted to the
few extant populations in southern Ohio. However, in 1990, during a Missouri
Natural Features Inventory of Texas County (Ryan and Smith, 1991), Bill Summers
located a new population. The insights from this find led to the rapid
discovery of additional populations (mostly by keen‑eyed Summers). Amazingly,
by 1996, about 80 populations had been documented as growing in the state. The
secret to these finds is that C. porteri exists mostly as vegetative
colonies, with flowering uncommon and very sporadic. Even when they flower,
plants fail to produce mature fruits, for reasons that are not presently clear
(most populations may consist of individual, self‑incompatible clones or
there may be other genetic barriers to seed set). Vegetatively, the plants are
distinct within their habitats. They occur as large, loose colonies of
scattered tufts and are characterized by long rhizomes, membranous ligules, and
glaucous, bluish green herbage. Other bluish green species, such as some
species of the wild rye genus Elymus, have shorter ligules, lack well‑developed
rhizomes, and occur as tufts or clumps. Agrostis perennans (Walter)
Tuck., upland bent, another bluish green species with membranous ligules, has
narrower leaf blades, and thinner stems that sometimes root at the lower nodes,
but also lacks rhizomes.
The other subspecies, ssp. porteri, is a high
polyploid (2n=84–104) that differs morphologically from ssp. insperata
in its light green herbage and leaf sheaths with a dense beard of long,
spreading hairs at the tip (Greene, 1980, 1984). It is distributed mostly in
the Appalachian Mountains from New York to Virginia and with western outliers
in Kentucky and Tennessee. The two subspecies occur in relatively close
proximity in western Kentucky.