Lectotypification and Taxonomic Notes for Porotrichum cobanense C. M.

Abstract

The lectotype of Porotrichum cobanense C. M. is established. Description and illustration of the type are presented with taxonomic notes on the species. The name Porotrichum cobanense C. M. has been in common usage since Miiller's original description in 1897. Originally described from near Coban, Guatemala, Brotherus (1925) expanded its range to include Panama. Wagner's treatment of Neckeraceae for North America (1951) has provided the most recent and complete distribution as follows: Mexico, Costa Rica, Cuba, El Salvador, Guatemala, Haiti, Jamaica, Panama and Puerto Rico. Modem synonymy for this species is uncomplicated, although taxonomically the species is often difficult to determine. Porotrichum pringlei Card. has been regarded as synonymous with P. cobanense by Crum (1951), Wagner (1951), and Crum and Steere (1957). Porotrichum undulatulum C. M. has also been included in synonymy by Wagner (1951) and Crum and Steere (1957); although excluded entirely by Bartram (1949). Difficulties in correct determination most often occur with specimens of Porotrichum longirostre (Hook.) Mitt., P. plagiorhynchum Ren. & Card., and Thamnobryum tumidicaule (Wagn.) Bowers. Taxonomic confusion within the entire genus, Porotrichum, is largely due to uncertain typification. MiUller (1897) cited the type specimen of P. cobanense as: Habitatio. In sylva primaeva prope Coban ad arbores. 4800 ped. altum: H. v. Tiirckheim 14 Feb. 1886 sterile legit. Hb. Levier in his publication Bryologia Guatemalensis ex Collectionibus Domin. Bernoulli and Cario (1866-1878) v. Tiirckeim et Aliorum. Many of Tiirckheim's specimens cited in this article lack collection numbers, necessitating type selection based upon comparison of label data on existing specimens. Two collections are available for consideration as type material. One specimen (H-BR) bears the following label data: 27. Porotrichum cobanense C. M. Guatemala, Alta Vera Paz. AufBaumsliimmen in Hochwalde oberhalb Coban. 4800', 14 Feb. 1886, legit von Tiirckheim (ex herb. Levier). A second specimen (BM) and fragments of this specimen (FH-Bartram, NY) bear label data equally suitable for type selection (Fig. 1). It is my choice to designate the specimen from the British Museum as the lectotype based upon the considerations given in the following discussion. Type: Bryotheca E. Levier, No. 31. Porotrichum cobanense C. Muell. spec. (in lit. 1891). Guatemala, Alta Vera Paz, in truncis arb. silvaeprope Coban, 14 Feb. 1886, H. v. Tiirckheim, determ. D. C. Milller. (Lectotypus, des. mihi-BM), NY (fragment of lectotype); FH-Bartram (fragment of NY specimen). Specimen No. 27 (H-BR) is rejected from consideration because it represents a duplicate from Levier's Herbarium bearing a handwritten label with the name Porotrichum cobanense C. M. in Brotherus' handwriting (presumably named by Brotherus after receiving the specimen). Furthermore, the specimen contained in the packet represents another taxon, Porotrichum aff. plagiorhynchum. Specimen No. 31 (BM) is more suitable for the lectotype because it was determined by MUiller and the annotation following the name nov. spec. (in lit. 1891) represents a more definite link to Miiller for purposes of his original description. A final consideration is the fact that the BM specimen falls within the range in variation of the species as is represented among general collections. Both isolectotypes appear to be derived from the lectotype. The NY specimen bears the label P. undulat[ul]um C. M. in the handwriting of Elizabeth Britton. The contents consist of two elements. One, no. 7742 (determined by Brotherus), possibly represents authentic material of Thamnium undulatulum (C. M.) Broth.; and the other includes three stem fragments matching the BM specimen and an inner label bearing the same data as the BM specimen. Notes accompanying these fragments indicate a loan of the material to E. B. Bartram in September 1926. The specimen at FH-Bartram, consisting of a branch fragment, was apparently retained by Bar-