Sticherus interjectus (Jermy & T.G.Walker) J.Gonzales, 2011

Gonzales, Jasivia & Kessler, Michael, 2011, A synopsis of the Neotropical species of Sticherus (Gleicheniaceae), with descriptions of nine new species, Phytotaxa 31, pp. 1-54 : 28-29

Sticherus interjectus (Jermy & T.G.Walker) J.Gonzales , comb. nov.

Gleichenia interjecta Jermy & Walker (1985: 2) . Type: — TRINIDAD & TOBAGO. Trinidad : Arima-Blanchisseouse Road, ca. 10°58’ N, 61°10’ W, 60 m, Jermy 11164 (holotype BM!) .

Distribution and ecology: —Forms mixed colonies with Sticherus ferrugineus and S. remotus along forest edges and roadsides at 60–300 m, mainly in the northern mountain range of Trinidad. Also known from scattered specimens from Grenada, Venezuela, Guyana, and Suriname, and to be looked for elsewhere where the parental species grow together, i.e., in Central America, northern South America, and the Caribbean Islands.

Notes: —This species was described by Jermy & Walker (1985) based on a survey of the caryology of the S. bifidus complex in Trinidad. They recognized S. interjectus as a tetraploid of allopolyploid origin with S. ferrugineus and S. remotus as parental taxa. Accordingly, morphologically this species is intermediate between S. ferrugineus and S. remotus . It can be distinguished from S. ferrugineus by its robust growth with visibly thicker branches, longer and overlapping aphlebiae, more chartaceous blades, longer and often somewhat curved segments, and more remote segments on the 1 st branch. Relative to S. remotus , this species has more closely spaced segments (except on the 1 st branch), is larger and more robust, has generally larger scales, more and paler scales on the fiddleheads, and sometimes bears arachnoid scales on the abaxial segment surfaces. Further diagnostic characters are found among the scales. Typically, S. interjectus has scales on the buds and abaxially on the branches that are bicolorous with almost black scale bodies and whitish margins. The bud scales have widened bases and long-acuminate apices whereas S. ferrugineus has uniformly lanceolate scales with square bases and S. remotus has short, triangular scales. The abaxial midvein scales are stellate, usually whitish, and sometimes have darkened cilia. Sticherus remotus has similar scales, whereas those of S. ferrugineus are larger and lax. Sticherus interjectus is also very similar to and possibly conspecific with S. nigropaleaceus (for further details see notes under that species).

Sticherus interjectus may also be confused with the triploid hybrid taxa occurring in Trinidad, S. × subremotus and S. × pseudobifidus. This is especially due to the fact that the hybrids are morphologically quite variable. Usually, they have branches of unequal length with somewhat irregularly placed segments. However, the main characters distinguishing S. interjectus from these hybrids are the bud and adaxial branch scales that have more regularly defined outlines, cell patterns, and color patterns. In S. × subremotus and S. × pseudobifidus adjacent scales on a given bud are highly variable with respect to shape and color and have irregular cell patterns. Jermy and Walker (1985) also described differences in the indument density on the abaxial segment surfaces between these three taxa, but closer examination of more specimens has convinced us that this is not a reliable character.