Microgramma

Smith, Alan R., Kessler, Michael, León, Blanca, Almeida, Thaís Elias, Jiménez-Pérez, Iván & Lehnert, Marcus, 2018, Prodromus of a fern flora for Bolivia. XL. Polypodiaceae, Phytotaxa 354 (1), pp. 448-450 : 448-450

Key to the Bolivian species of Microgramma

1 Rhizomes ca. 3 mm diam., bearing globose tubers; rhizome scales bicolored, mostly round, a few slightly ovate ........ M. bifrons

– Rhizomes 1–10 mm diam., lacking tubers; rhizome scales concolorous to bicolored, mostly lanceolate ....................................... 2

2 Blades with conspicuous and sometimes abundant lanceolate to subulate or minute round peltate scales on the tissue between the midrib and blade margins ................................................................................................................................................................. 3

– Blades glabrous, with hairs on the blade tissue, or with arachnoid scales; if lanceolate scales present, these mainly along midribs ........................................................................................................................................................................................................... 8

3 Blades with conspicuous and sometimes abundant lanceolate to subulate scales on the tissue between midribs and blade margins; fronds monomorphic or dimorphic ................................................................................................................................................... 4

– Blades with minute, round to stellate, peltate scales on the tissue between midribs and blade margins; fronds monomorphic ..... 7

4 Fronds monomorphic, fertile and sterile blades similar in size ................................................................................... M. latevagans

– Fronds dimorphic, the sterile blades 2–6 times broader than the fertile ones .................................................................................. 5

5 Sterile blades 0.8–2.5 cm long; blade scales subulate, setiform from abruptly expanded bases, geniculate, rarely applanate; rhizome scales spreading, the tips filiform ......................................................................................................................................... M. nana

– Sterile blades 3–8 cm long; blade scales narrowly deltate from scarcely expanded bases, applanate; rhizome scales appressed, the tips not filiform ................................................................................................................................................................................. 6

6 Veins obscure abaxially; sori overlapping margins of fertile fronds ................................................................................ M. reptans

– Veins visible, at least abaxially; sori borne abaxially, not overlapping margins of fertile fronds ............................... M. tobagensis

7 Blades firm-herbaceous; veins distinct on both surfaces; blade surfaces with minute, stellate scales mostly <0.1 mm in diameter; rhizome scales erose, translucent ............................................................................................................................. M. dictyophylla

– Blades coriaceous; veins indistinct on both surfaces; blade surfaces with circular scales mostly 0.2–0.3 mm in diameter; rhizome scales toothed, opaque .................................................................................................................................................... M. percussa

8 Rhizome scales entire ....................................................................................................................................................................... 9

– Rhizome scales ciliate, denticulate, or erose .................................................................................................................................. 10

9 Sori elongate to linear; primary lateral veins much thicker and more prominent than the others; laminar apices acute .................... ................................................................................................................................................................................ M. persicariifolia

– Sori round; primary lateral and other veins equally prominent; laminar apices caudate .................................................. M. thurnii

10 Rhizome scales erose, bicolorous, each with a sharply differentiated brown median streak and broad whitish margins ............. 11

– Rhizome scales entire, ciliate, concolorous or indistinctly bicolorous .......................................................................................... 12

11 Rhizomes broadly flattened, to 30 mm wide; blades lanceolate, 2–9 cm wide ...................................................... M. megalophylla

– Rhizomes slightly flattened, 0.5–1.0 mm wide; blades linear, 4–10 mm wide .................................................... M. rosmarinifolia

12 Leaves monomorphic (fertile and sterile leaves similar in size and shape) or differing only in size, fertile blades lanceolate; abaxial midrib scales lacking or few ........................................................................................................................................................... 13