Bucklandiella sect. Laevifoliae
Plants moderately sized to large, fairly slender to coarse and rigid, often hoary. Stems 1–12 cm long, creeping, curved-ascending to erect, sparingly or profusely branched. Leaves lanceolate, straight to strongly curved; margins recurved to revolute on both sides to the apex, or less often to 2/3–3/4 of the leaf length, 1-stratose or less often 2-stratose; muticous or piliferous, awns often long, erect, flexuose, flattened, distantly denticulate at the margins and sometimes spinulose on the abaxial side; costa 3–4-stratose and strongly convex abaxially in the proximal portion; alar cells undifferentiated; basal marginal border absent. Inner perichaetial leaves strongly modified, hyaline and epilose, or very seldom shortly piliferous and then chlorophyllose close to the apex. Peristome teeth with a basal membrane.
North America, Europe, Atlantic Islands (Azores, Canary Islands, Iceland, Madeira).
Species 7 (5 in the flora).
The strongly differentiated innermost perichaetial bracts that are ovate, epilose, and hyaline to yellowish hyaline throughout are diagnostic of section Laevifoliae. This is a Euro-American taxon consisting of two species that are endemic to Europe, three endemic to North America, and two that are Euro-American disjuncts.
|1||Leaves epilose, with a chlorophyllose apex, awns absent||> 2|
|1||At least some leaves with a short or long, hyaline to subhyaline awn||> 4|
|2||Leaf margins recurved to 2/3-3/4 of the leaf length; alar cells differentiated, short, thick- walled and porose, forming a well-defined, sometimes auriculate group.||Bucklandiella pacifica|
|2||Leaf margins recurved to revolute to the apex; alar cells not or weakly differentiated||> 3|
|3||Leaf margins 1-stratose, occasionally with 2-stratose patches and smooth in the distal part; costa broader, 80-100 µm, and mostly (3-)4-stratose basally (epilose plants).||Bucklandiella affinis|
|3||Leaf margins usually 2-stratose for 1-3 cell rows, wavy and lumpy in the distal part; costa narrow, 50-80 µm, and usually 3-stratose basally (epilose plants).||Bucklandiella venusta|
|4||Costa broadly canaliculate in mid leaf, moderately convex on the abaxial side and with 4-9 cells on the adaxial side||> 5|
|4||Costa narrowly canaliculate or carinate in mid leaf, strongly convex on the abaxial side and with 3-4 adaxial cells||> 6|
|5||Plants moderately robust and less coarse; leaf margins 1-stratose with infrequent 2-stratose patches and smooth distally; awns weakly flexuose.||Bucklandiella heterosticha|
|5||Plants coarse and robust; leaf margins 2-stratose for 1-3 cell rows and lumpy distally, broadly recurved to revolute throughout; awns stiff, not flexuose.||Bucklandiella obesa|
|6||Leaf margins usually 2-stratose for 1-2(-3) cell rows and lumpy in the distal portion; awns stout, not or weakly flexuose, strongly spinulose||> 7|
|6||Leaf margins usually 1-stratose with occasional 2-stratose spots and not lumpy distally; awns soft, usually flexuose and faintly spinulose||> 8|
|7||Plants robust, almost unbranched; costa broad, 80-120 µm with 4-9 adaxial cells in the basal portion; leaves long, 3-4 mm.||Bucklandiella obesa|
|7||Plants small to medium-sized, copiously branched; costa narrow, 50-80 µm with 3-5 adaxial cells in the basal portion; leaves short, 1.7-2.4 mm.||Bucklandiella venusta|
|8||Costa carinate and predominantly 3-stratose in the middle and lower distal portion.||Bucklandiella affinis|
|8||Costa canaliculate and predominantly 2-stratose in the middle and lower distal portion||Bucklandiella heterosticha|