Ditrichum ambiguum

Best

Bull. Torrey Bot. Club 20: 117. 1893,.

Treatment appears in FNA Volume 27. Treatment on page 451. Mentioned on page 456, 458.

Plants in loose to dense tufts, green to yellowish green, becoming yellowish-brown with age, dull. Stems 0.7–2 cm, with a few reddish rhizoids at the base. Leaves erect-spreading, somewhat crisped when dry, 1.5–4.5 mm, lanceolate to linear-lanceolate, channelled, lamina with a few scattered 2-stratose cells midway between margins and costa in median to distal part of leaf; margins broadly recurved from the base to near mid lamina, weakly to strongly serrulate from mid lamina to apex, entire or serrulate at the somewhat blunt apex, 2-stratose distally and sometimes extending inward for several cells; costa distinct, percurrent, occupying 1/6–1/3 the width of the leaf base; lamina cells thick-walled, distal cells quadrate, irregularly subquadrate to shortrectangular, 8–24 × 4–8 µm, becoming broader and longer near the base. Specialized asexual reproduction unknown. Sexual condition dioicous. Seta red, 1–2 cm, erect. Capsule erect, usually straight and symmetric or sometimes slightly curved, dark-brown or reddish, cylindric, 1.5–3 (–3.2) mm, occasionally slightly enlarged at base; operculum rostrate, 0.4–0.8 mm; peristome red, 200–500 (–800) µm, twisted when dry, teeth divided to near base into two equal filaments, strongly papillose to spiculose. Spores round, 6–13 µm, appearing smooth to minutely papillose.


Phenology: Capsules mature spring and summer (Apr–Jul).
Habitat: Moist, sandy or sometimes clay banks, soil on upturned stumps, crevices of sandstone cliffs, often in clearings along roads
Elevation: low to moderate elevations (100-500 m)

Distribution

V27 651-distribution-map.gif

B.C. (including Queen Charlotte Island), Alaska, Calif., Oreg., Wash., Central America (Guatemala), Central America (Panama)

Discussion

Ditrichum ambiguum, a western species, is very close to an eastern species, D. tortuloides, but differs in the following morphological characters: stems often branched and taller, 7–20 mm compared to the shorter, 2–5 mm, usually simple stems of D. tortuloides; leaf margins broadly recurved, entire or serrulate at a somewhat blunt apex, compared to the narrowly recurved, serrate to strongly serrate margins from mid-leaf to an acute apex in D. tortuloides; leaf laminae with 2-stratose margins and occasional 2-stratose regions between the margins and the costa in the middle to distal half of the leaf, compared to the 2-stratose regions only on the margins in D. tortuloides; capsules dark brown to reddish, 1.5–3.2 × 0.2–0.5 mm, straight and symmetric to rarely slightly arcuate with an occasionally slightly swollen base, compared to the yellow or light brown, 1–2.5 × 0.2–0.3 mm, curved and asymmetric capsules often with a swollen base in D. tortuloides. The geographic ranges of the two taxa are quite disparate. The species has been reported outside North America by B. H. Allen (1994), from Guatemala and Panama.

Selected References

None.

Lower Taxa

None.

"um" is not declared as a valid unit of measurement for this property.

... more about "Ditrichum ambiguum"
forming a marginal border +  and not differentiated +
Rodney D. Seppelt +, Robert R. Ireland Jr. +  and Harold Robinson +
cucullate +
0.3 cm3 mm <br />0.003 m <br /> (0.32 cm3.2 mm <br />0.0032 m <br />) +
reddish;dark-brown +
curved +  and straight +
cleistocarpous +
cylindric +
enlarged +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
Several (?) +  and Few (?) +
distinct +
subpercurrent +
1/6 +  and 1/3 +
1/6 width of leaf base;1/3 width of leaf base +
shortrectangular +  and isodiametric +
dioicous +, sexual +  and asexual +
subquadrate +  and quadrate +
B.C. (including Queen Charlotte Island) +, Alaska +, Calif. +, Oreg. +, Wash. +, Central America (Guatemala) +  and Central America (Panama) +
low to moderate elevations (100-500 m) +
Moist, sandy or sometimes clay banks, soil on upturned stumps, crevices of sandstone cliffs, often in clearings along roads +
papillose +  and smooth +
dioicous +, monoicous +  and sexual +
flexuose +
lanceolate +  and linear-lanceolate +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.45 cm4.5 mm <br />0.0045 m <br />) +
serrulate +  and entire +
denticulate +
0.04 cm0.4 mm <br />4.0e-4 m <br /> (0.08 cm0.8 mm <br />8.0e-4 m <br />) +
with a longer , broader sheathing base +  and differentiated +
on short branches +  and axillary +
Capsules mature spring and summer (Apr–Jul). +
filamentous +
Bull. Torrey Bot. Club +
flexuose +
elongate +
1 cm10 mm <br />0.01 m <br /> (2 cm20 mm <br />0.02 m <br />) +
papillose +
sometimes +  and simple +
reaching 2 cm +  and short +
0.7 cm7 mm <br />0.007 m <br /> (2 cm20 mm <br />0.02 m <br />) +
Ditrichum ambiguum +
Ditrichum +
species +
papillose +
divided +
specialized +
synoicous +, paroicous +, autoicous +, dioicous +  and sexual +
yellowish-brown +, green +  and yellowish green +
small +  and medium-sized +