Plesioneuron ophiura
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Notes
Brass 12465, from the same locality as the type but "in young forest at foot of rock-slide, a clump of fern with fronds to 180 cm long" (specimen at L) was named Lastrea costu- lisora by Copeland, and so accepted by me in 1975, but agrees with the type of P. ophiura in deeply lobed pinnae, and probably represents the fully developed form of the same species; its description follows. Stipe 100 cm long; basal scales 10x1.5 mm. Lamina 100 cm long; pinnae 22 pairs, lower ones 7 cm apart; basal pinnae with stalks 3 mm long and 3-4 pairs of basal lobes gradually reduced and separately adnate to costa; all upper pinnae with much-reduced basal lobes; aerophores black, firm, more than 0.5 mm long. Largest pinnae 24 x 2.5-3.0 cm, at base lobed almost to costa, distally to 1 mm from costa, apex with cauda 3 cm long; lobes on acroscopic side of pinna straight, on basiscopic side somewhat falcate; costules 6 mm apart; veins to 20 pairs; sporangia sometimes with a small shrivelled gland, rarely a short seta. If this is included in P. cos- tulisorum, I think that the type of P. ophiura should also be so included.