Christella

Smith, Alan R. & Kessler, Michael, 2017, Prodromus of a fern flora for Bolivia. XXX. Thelypteridaceae, Phytotaxa 331 (1), pp. 1-34 : 19-20

Key to the Bolivian species of Christella (including Amblovenatum and Cyclosorus )

1 Basal veins from adjacent segments united at an obtuse angle below each sinus with an excurrent vein to sinus ......................... 2

– Basal veins from adjacent segments connivent at, or running to, each sinus, or joining at an acute angle just below sinus .......... 4

2 Proximal pinnae the longest or nearly so; costae abaxially with ovate scales; blades abaxially with sessile orangish or reddish, hemispherical glands; rhizomes very long-creeping, blackish, nearly naked .............................................. Cyclosorus interruptus

– Proximal pinnae reduced; costae abaxially lacking scales; blades abaxially lacking glands or with short-stipitate, light yellow or orangish glands; rhizomes relatively short-creeping, brown, scaly ................................................................................................. 3

3 Costae abaxially with predominantly short hairs uniform in length, mostly 0.1–0.2 mm long; petioles and rachises usually purplish brown ................................................................................................................................................................................. C. dentata

– Costae abaxially with most hairs> 0.3 mm long with some exceeding 0.5 mm; petioles and rachises stramineous to tan ................ ......................................................................................................................................................................................... C. hispidula

4 Rhizomes suberect to erect, hidden by old leaf bases; proximal pinnae often auriculate at acroscopic bases ................................ 5

– Rhizomes creeping, readily visible; proximal pinnae not auriculate ............................................................................................... 6

5 Blades adaxially glabrous on costules and veins; petiole base scales tan, ovate to ovate-lanceolate, glabrous or nearly so, dull ...... .............................................................................................................................................................................................. C. patens

– Blades adaxially hairy on costules and veins; petiole base scales brown, lanceolate, pubescent, shining ..................... C. schizotis

6 Several pairs of proximal pinnae greatly reduced; blades adaxially with numerous hairs between veins .................... C. conspersa

– Proximal pinnae not reduced; blades adaxially glabrous between veins ......................................................................................... 7

7 Glands abaxially along veins and costules sulfur-yellow, sessile, especially toward the segment tips and among sporangia; costae abaxially scaleless .................................................................................................................................. Amblovenatum opulentum

– Glands absent along veins and costules abaxially and among sporangia; costae abaxially with scales .......................................... 8

8 Costal hairs mostly> 0.2 mm long, dense; costal scales numerous ................................................................................... C. clivalis

– Costal hairs ca. 0.1 mm long, moderately dense; costal scales relatively few .................................................................. C. grandis