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Dicranella pacifica W. B. Schofield [Dicranaceae]
map of distribution

Plants to 20 mm high, in rather dense turfs, light green to pale green. Leaves distantly inserted, not falcate, spirally inserted without obvious ranking, to 5 mm long, about 8–10: 1, not significantly keeled. Leaves with a strong contraction at 1/3 to 1/4 way up the leaf and with the limb rather abruptly contracted to the narrow subula. Leaves erect but slightly distorted when dry, erect-spreading when moist. Lamina cells unistratose and smooth but marginal cells bistratose, and sometimes bistratose near the apex. Alar cells not differentiated. Basal cells uniform throughout, in regular rows, to 15 µm broad, 3–6: 1, rectangular with uniformly thin walls. Median cells to 15 µm wide, about 3–4: 1, thin-walled with lumen: wall ratio 1, with ends walls transverse of nearly so, rather thin walled. Subula with lamina 1–6 cells wide but with distal portion narrowing to extinction, with those cells short rectangular, to 12 µm broad, 3–4: 1, arranged in regular rows, thin-walled with lumen: wall ratio 5–8: 1. Abaxial cells of costa narrowly linear, to 10 µm wide, about 6: 1; adaxial cells similar to adjacent lamina' cells. Costa about 1/10 of leaf base but filling most of subula, short excurrent. Costa cross-section at mid-leaf flattened-crescentic, 3.5–4.5: 1 with a well-defined single layer of guide cells, and with a strong abaxial but a weak and narrow adaxial stereid bands and with well-demarcated dorsal and ventral epidermises. Margin recurved from base to above the middle, sometimes serrulate near apex. Rhizoids very sparingly produced, to 20 µm in diameter at insertion, pale to red-brown, mostly on abaxial leaf bases on extreme base of plant. Axillary hairs to 350 µm long, more than 10 cells, uniform throughout with all cells thin-walled and of uniform diameter. Stem cross-section rounded pentagonal, with poorly defined central strand, with very thin-walled inner cortical cells, and with only 1–3 layers of thicker walled smaller cells in the outer cortex. Dioicous with male and female plants similar. Perichaetial leaves similar to the vegetative leaves. Seta to 10 mm, reddened when mature, straight, smooth. Capsule curved and asymmetrical with the mouth oblique and with the urn short cylindric, to 1.25 mm long, about 2: 1, neither sulcate nor strangulate, not at all strumose. Annulus absent. Calyptra cucullate, glabrous, covering about 1/2–2/3 of urn. Operculum inclined, rostrate, 2/3 or more of urn length. Peristome reddish-brown, to 500 µm long, sparingly papillose above, bifid nearly to base, shortly connate basally. Exothecial cells irregular in size and shape, rectangular with oblique end-walls, not in regular rows, to 35 µm wide, 2–5: 1, thick-walled with lumen: wall ratio 2–3: 1. Suboral exothecial cells quadrate with rounded lumens in 4–5 rows, reddened, to 25 µm wide, very thick-walled with lumen: wall ratio 2–3: 1. Stomata scarce, restricted to neck of capsule, phaneroporous and vertical pored. Spores spherical, to 18 µm, lightly papillose.

Mail a correction to Paul Wilson ·
IllustrationsLawton 1971.
NotesSee Schofield (1970) for a table of characters separating D. pacifica from D. varia.
VouchersDel Norte Co.: Bear Basin Butte, Six Rivers National Forest, Norris 8095.

Elevation by latitude plot for Dicranella pacifica
   in California

Generated: Sun Jul 15 20:16:44 2018