1. Stem leaves gradually narrowed into short to long apices … 2.
1. Stem leaves abruptly narrowed into short to long apices … 14.
2. Stem leaf apices short, apiculate, acute, and/or blunt, ± homomallous … 3.
2. Stem leaf apices longer, ± not or variously bent … 5.
3. Terminal cell of stem leaves distinctly smaller than apical cells, median cells ± long fusiform … 4.
3. Terminal cell of stem leaves similar in size to apical cells, median cells linear; seta papillose throughout … B. rutabulum
4. Leaves ± homomallous; stem leaf apices apiculate, alar cells in discrete group, areolation narrow and smaller; autoicous; setae papillose above … B. plumosum
4. Leaves straight; stem leaf apices acute, alar cells in columns gradually transitioning into basal cells, areolation lax; sexuality and sporophytes unknown … B. rivularioides
5. Stem leaves with long ± broad decurrencies … 6.
5. Stem leaves with short or weak decurrencies … 8.
6. Pseudoparaphyllia orbicular to ovate-apiculate or acute; autoicous; setae papillose … B. rutabulum
6. Pseudoparaphyllia ovate-acuminate; dioicous; setae smooth … 7.
7. Stem leaves with lax areolation (median cells ca. 10.6 µm), alar and basal cells weakly differentiated; costa with short lateral spurs extending into leaf lamina; margins entire … B. conostomum
7. Stem leaves with small and narrower areolation (median cells ca. 6-8 µm), alar and basal cells differentiated; costa rarely with short lateral spurs; margins serrulate to serrate … B. ruderale
8. Stem leaves strongly plicate … 9.
8. Stem leaves not to weakly plicate or only at base … 11.
9. Stem leaves mostly greater than 2.0 mm long, elongate-triangular, long tapering acuminate; autoicous; setae smooth … B. austroglareosum
9. Stem leaves mostly less than 2.0 mm long, ovate to broadly ovate short- to long acuminate; synoicous, autoicous or dioicous; setae smooth or papillose …. 10.
10. Leaf areolation loose, basal and alar cells more lax than median cells; dioicous; seta smooth … B. ruderale
10. Leaf areolation more compact, basal cells slightly broader than median cells; alar cells small indiscrete groups; synoicous or rarely autoicous; setae papillose … B. praelongum
11. Stem leaves erect to spreading; branch leaves ± squarrose when moist, ± curved; alar cells small, as wide as basal cells, indiscrete groups; autoicous … B. occidentale
11. Stem leaves straight, imbricate erect when moist; branch leaves never squarrose, alar cells medium-sized to lax ± inflated, wider than basal cells; autoicous or dioicous … 12.
12. Plants dioicous … B. ruderale
12. Plants autoicous … 13.
13. Pseudoparaphyllia orbicular to ovate-apiculate or acute; setae with tall dense papillae … B. rutabulum
13. Pseudoparaphyllia ovate-acuminate; setae with low diffuse papillae … B. chocayae
14. Stem leaves with long, ± broad decurrencies; autoicous; setae papillose … B. rutabulum
14. Stem leaves with weak or short decurrencies; autoicous or dioicous; setae smooth or papillose … 15.
15. Stem leaf areolation lax, median leaf cells ca. 10 µm wide; costa with prominent short lateral spurs extending into lamina; setae smooth … B. conostomum
15. Stem leaf areolation narrower, median leaf cells averaging 7 µm wide; costa lacking lateral spurs; setae papillose … B. cirriphylloides