Dicranella cerviculata W. P. Schimper 1856

The leaves of Dicranella cerviculata are not wide-spreading from a clasping base, and the perichaetial leaves are scarcely differentiated from stem leaves. The costa occupies about ¹/2 of the leaf base. The nodding, asymmetric, strumose capsule becomes variously striate or furrowed when dry and empty. Bartleya ohioensis, known solely from sterile material from West Virginia and Ohio, differs from D. cerviculata only in having a somewhat better development of stereids in the costa. The report from Maryland (as B. ohioensis) was by H. Robinson and C. F. Reed (1987) and from Wisconsin by F. D. Bowers and S. K. Freckmann (1979). In Northwest Territories it is known only from Great Bear Lake and the Tuktoyaktuk Peninsula.

Plants minute to small, 2–10 mm high, dull green or yellowish brown, in tufts. Stems erect, simple or branched. Leaves 1.0–1.5 mm long, lower ones slightly falcate, narrowly lanceolate, upper ones erect-spreading to flexuose or falcate-secund, linear-lanceolate, abruptly narrowed from a sheathing base to a long, channeled subula; margins plane, entire or serrulate near the apex; costa broad, occupying ca. ½ the leaf base width, long-excurrent, smooth at back; upper leaf cells short- to long-rectangular, 16–40 µm × 4–8 µm; lower cells shorter. Dioicous. Perichaetial leaves similar to upper stem leaves. Setae straight, (5–)8–10(–15) mm long, yellow to yellowish brown; capsules ovoid, inclined, slightly curved, strumose, furrowed when dry and empty; opercula slenderly long-rostrate, curved, 0.5–1.0 mm long; annuli in 1 row of small, thick-walled cells, persistent; peristome teeth divided to the middle or lower, vertically pitted-striolate below. Spores 15–21 µm in diameter, smooth or finely roughened.

Plants to 6 mm (or rarely, when sterile, to 30 mm), in dull, yellow-brown tufts. Leaves 2.5-3 mm, erect-spreading and flexuose or secund, linear-lanceolate, gradually subulate, slenderly acute or ± blunt; margins erect, entire or slightly serrulate near the apex; costa long-excurrent, occupying about ¹/2 the leaf base; distal cells long-rectangular, 5-10:1. Sexual condition dioicous. Seta 5-6(-12) mm, yellow, becoming brownish with age. Capsule 0.7-1 mm, nodding and curved-asymmetric, short-oval, strumose, furrowed when dry and empty; annulus a single row of small, persistent cells; operculum slenderly long-rostrate, curved; peristome teeth 270-350 µm, divided ¹/2 length distally or more. Spores 16-21 µm, smooth to indistinctly roughened.

Distribution: Europe, Japan, North America, and Russian Far East.

Habitat: on wet sandy soil near streams, roadsides or open fields.

Dicranum cerviculatum Hedwig, Sp. Musc. Frond., 149. 1801; Bartleya ohioensis H. Robinson; Dicranella cerviculata var. americana Grout; D. cerviculata var. pusilla (Hedwig) Schimper; D. ohioensis (H. Robinson) H. A. Crum; D. polaris Kindberg; D. pusilla (Hedwig) E. Britton; Dicranum pusillum Hedwig

Ojanukkasammal (Dicranella cerviculata) on nukkasammalten sukuun kuuluva sammal, jota tavataan koko Suomessa.

Dicranella cerviculata là một loài Rêu trong họ Dicranaceae. Loài này được (Hedw.) Schimp. mô tả khoa học đầu tiên năm 1856.