Carex and other sedges (Cyperaceae) of San Mateo County and Santa Cruz Mountains Bioregion's Journal

B. maritimus subsp. paludosus vs. B. robustus

• Styles all or mostly 2-fid, vs. Styles 3-fid or a few 2-fid
• Achenes usually biconvex, rarely compressed trigonous vs. Achenes mostly trigonous, or biconvex or compressed-trigonous with low, rounded abaxial angle
• Leaf sheath fronts usually membranous at mouth, veins diverging proximal to summit leaving triangular, veinless area vs. Leaf sheath fronts usually papery at mouth, veins reaching nearly to summit
• Floral scales hyaline vs. Floral scales nearly opaque, papery
• Floral scale awns 0.25 mm at base vs. Floral scale awns 0.5 mm at base [~0.3-0.5]
• Anthers yellow vs. Anthers brownish orange

words and shapes

• Trigonous = 3-angled
• Biconvex = Lenticular = Lens-shaped
• Obscurely trigonous = compressed trigonous = Plano-convex [flat on one side and convex on the other]

B. robustus -- Peri biconvex to obscurely trigonous; Floral scale awns 0.5 mm at base

FNA genus Bolboschoenus

1. Inflorescences with all spikelets sessile or not more than 1/2 on evident branches; perianth bristles not persistent on shed achene or 1–few bristles weakly persistent; achenes biconvex or compressed-trigonous with low, rounded abaxial angle; achene epidermal cells appearing greatly enlarged in cross section, 2–3+ times deeper than wide; styles 2–3-fid; habitats brackish to saline. . . . > 2
2. Inflorescences with all or most spikelets on evident, elongated branches; perianth bristles tightly attached to shed achene, rarely some or all falling separately; achenes equilaterally trigonous to compressed-trigonous or rarely some biconvex; achene epidermal cells appearing small in cross section, isodiametric or very rarely enlarged and to 3 times deeper than wide (in B. novae-angliae); styles mostly 3-fid; habitats fresh to slightly brackish. . . . > 3
3. Floral scales hyaline, membranous, awns 0.25 mm wide at base; anthers yellow, rarely orange; styles 2-fid, rarely 3-fid; achenes usually biconvex, rarely compressed trigonous; leaf sheath fronts usually membranous at mouth, veins diverging proximal to summit leaving triangular, veinless area. . . . Bolboschoenus maritimus
4. Floral scales nearly opaque, usually papery, awns 0.5 mm wide at base; anthers brownish orange; styles 3-fid or a few 2-fid; achenes mostly trigonous; leaf sheath fronts usually papery at mouth, veins reaching nearly to summit. . . . Bolboschoenus robustus