Meniscium

Smith, Alan R. & Kessler, Michael, 2017, Prodromus of a fern flora for Bolivia. XXX. Thelypteridaceae, Phytotaxa 331 (1), pp. 1-34 : 26

Key to the Bolivian species of Meniscium

1 Pinnae (both fertile and sterile) serrate, at least toward the pinna apices ......................................................................................... 2

– Pinnae (both fertile and sterile) entire to subentire, undulate, or crenulate ...................................................................................... 3

2 Pinnae elliptic, sessile; distal pinnae not or only slightly reduced, apical pinna nearly as large as the lateral pinnae; costae and veins abaxially glabrous or with sparse hairs to 0.2 mm, laminar surface between veins glabrous ................................ M. consobrinum

– Pinnae lanceolate, generally pedicellate; distal pinnae gradually reduced, apical pinna much smaller than lower, lateral pinnae; costae and veins abaxially with moderate to dense hairs to 0.35 mm, laminar surface between veins also somewhat hairy ............ ........................................................................................................................................................................................ M. serratum

3 Receptacles or sporangial stalks with tubular yellow or orange glands ........................................................................................... 4

– Receptacles or sporangial stalks lacking tubular glands .................................................................................................................. 5

4 Fronds monomorphic; pinnae 4.5–7.5 cm wide; lateral veins of fertile pinnae 8–11 pairs per 3 cm; areoles 13–20-seriate ............. .................................................................................................................................................................................... M. andreanum

– Fronds subdimorphic; pinnae 2.5–4.5 cm wide; lateral veins of fertile pinnae 13–18 pairs per 3 cm; areoles 7–10-seriate ............. ........................................................................................................................................................................................ M. arcanum

5 Sporangial stalks and receptacles generally lacking hairs ................................................................................................................ 6

– Sporangial stalks each often bearing an acicular hair, or receptacles bearing numerous hairs, or sterile sporangia (sporangiasters) with such hairs ................................................................................................................................................................................ 12

6 Areoles of sterile pinnae about as broad as long, the secondary veins almost straight .................................................................... 7

– Areoles of sterile pinnae much shorter than broad, the secondary veins often curving (subsigmoid) ............................................. 8

7 Pinnae glabrous, the proximal ones subcordate, sessile ............................................................................................ M. andreanum

– Pinnae sparsely pubescent on the costae and veins, the proximal ones cuneate at bases, long-stalked ................... M. pachysorum

8 Costae, veins, and blades abaxially with numerous short-stipitate glands 0.1 mm long, hairs lacking ................. M. maxonianum

– Costae, veins, and blades abaxially lacking glands or nearly so, hairs present at least on costae and veins ................................... 9

9 Fronds 2–4 m; pinnae elliptic, 23–35 × 2.7–5 cm; buds lacking ............................................................................. M. pachysorum

– Fronds generally shorter; pinnae linear-lanceolate, generally <25 × 3.5(4) cm; buds sometimes present in axils of proximal pinnae ............................................................................................................................................................................................. 10

10 Pinnae rounded at bases, gradually tapering distally ................................................................................................ M. arborescens

– Pinnae cuneate at bases, widest at mid-pinna ................................................................................................................................. 11

11 Pinnae narrowly cuneate at bases, usually <2(2.5) cm wide; costae abaxially with adpressed, curved hairs; areoles 4–10(13)- seriate, about as broad as long on sterile fronds .................................................................................................... M. angustifolium

– Pinnae broadly cuneate, rounded, or truncate at bases, 1.5–4 cm wide; costae abaxially with mostly spreading, crispate or straight hairs; areoles mostly 8–16-seriate, broader than long on sterile fronds ......................................................................... M. lanceum

12 Hairs of costae and blades appressed abaxially; buds often in the axils of proximal pinnae ............................ M. membranaceum

– Hairs of costae and blades spreading abaxially; buds lacking ....................................................................................................... 13

13 Proximal pinnae of fertile fronds oblong to elliptic, or elliptic-lanceolate; sterile pinnae 6–12 lateral pairs per frond, 3.5–8 cm wide ........................................................................................................................................................................ M. chrysodioides

– Proximal pinnae of fertile fronds linear to lanceolate; sterile pinnae usually>12 pairs per frond, mostly 2.5–4 cm wide ........... 14

14 Abaxial surface of blades glabrous between veins; costal hairs abaxially 0.2–0.3 mm long .................................... M. hostmannii

– Abaxial surface of blades bearing erect acicular hairs between veins; costal hairs 0.5–1 mm long ......................... M. longifolium