— 292 — 



Obs. Chry sodium pellucens, Mett. Ann. sc. nat. V. 2:205. 1864, 

 from St. Anna in Columbia (Lewy) is probably a slightly abnormal form 

 of L. Lindigii with the lower pinnæ incised 1 /s of the way to the midrib, 

 the others deeply inciso-serrated, the lobes with acute teeth. The venation 

 does not differ from that of L. Lindigii. Only a single, sterile leaf is 

 known (HB). Baker (Syn. Fil. 419) considers this form, like the next 

 species, as a near ally of Acrostichum alienum. a species of a different 

 group {Gymnopteris proper of Presl and Fée). Baker's arrangement of 

 the species in the two subgenera of Acrostichum, Gymnopteris and Chry- 

 sodium, is very unsatisfactory, as the author, making use of the head 

 character for the two groups: distinct or no „main veins", is obliged to 

 place species of the closest alliance in different groups, and, on the other 

 hand, to unite in one subgenus, species of no or little affinity (for 

 example A. aureo-nitens, A. serratifolium, A. crinitum and A. aureum, 

 all placed under Chry sodium). 



5. Leptochilus opacus (Mett.) G. Chr. — Fig. 5 a—c. 



Syn. Chry sodium Mett. Ann. sc. nat. V. 2:204. 1864. 



Lamina folii sterilis late-oblonga, 3 dcm longa, pinnata, versus apicem 

 pinnatifida. Pinnæ 6 — 7 jugæ, erecto-patentes, elliptico-elongatæ, 15 — 20 cm 

 longæ, infra medium 3 — 3V2 cm latæ, acuminatæ, inferiores petiolo l cm longo 

 petiolatæ, basi longe et subæqualiter cuneatæ, superiores sessiles et basi 

 inferiore decurrentes, supremæ cam pinna terminali confluentes, glabræ 

 et omnino nudæ, membranaceæ, firmæ, opaco virides vel nigrescentes. 

 Margo pinnarum præsertim versus apicem serratus, vel duplo-serratus, 

 infra medium leviter serratus. Gostulæ conspicuæ, prominulæ. Maculæ 

 costales angustæ; ceteræ irreguläres, 5 — 6 seriatæ — sæpe 5 — 6 in serie 

 — rarissime appendiculatæ. Venæ exteriores liberæ marginem attingentes. 

 Petiolus versus basin squamis paucis lineari-acuminatis, subintegris instructus. 

 Rachis nuda. 



This species, known only in a single specimen, recedes from all the 

 other American species of the group by its terminal pinna and three 

 upper lateral ones being confluent: the upper portion of the leaf not 

 being truly pinnate. It is also marked by its dark colour and the long- 

 cuneated bases of the pinnæ. The venation is very irregular, resembling 

 mostly that of L. contaminoides , but the included free veinlets are 

 normally absent. The species, however, resembles closely the African 

 L. punctatus (L.) {Acrostichum punctulatum Sw.), receding only by its 

 more cuneate pinnæ and more irregular venation. 



Specimen examined: 



Columbia: Chucuri, Lindig, sine num. (HB). 



Fig. 5 a. Upper part of a sterile leaf, y h nat. size. — Fig. 5 b. Pinna, 

 3 /4 nat. size. — Fig. 5 c. Fragment, showing the venation, Z U nat. size. 



