Polytrichadelphus is stated to contain 25 species, probably less than 10. The genus is largely confined to the Southern Hemisphere. In the Neotropics about 5-7 species. Open premontane to páramo and puna in the tropical Andes; in exposed sites particularly on slopes, on soil, soil covered rocks. A distinguishing feature of this genus is the orange or reddish-orange spot found on the distal sheathing base. The genus is considered to be diverse in the northern Andes, an area of "secondary evolution" (Smith, 1971, see family reference); however given the variability and polymorphism within and adjoining populations, this diversity is more applicable to the numerous named species rather than actual taxa. At least some of the taxa exhibit gametophytic variation in stature as found in Pogonatum campylocarpon and Polytrichum juniperinum. There are a few collections from Colombia of a very small stature (ca. 1 cm) that may represent a new species. The majority of species listed here can be categorized as “Status Unknown.” Polytrichadelphus is the most notable genus in the family requiring a critical revision. At present Denilson Peralta is preparing a treatment of the genus.
Se afirma que Polytrichadelphus contiene 25 especies, probablemente 10 o menos, confinadas al hemisferio sur; posiblemente cinco especies en el Neotrópico. El género requiere una revisión minuciosa.
Status unknown:
Polytrichadelphus abriaquiae (Müll. Hal.) A. Jaeger, Ber. Thätigk. St. Gallischen Naturwiss Ges. 1877-78: 453. 1880. Catharinea abriaquiae Müll. Hal., Flora 58: 534. 1875. Type: Colombia. Antioquia, Abriaqui, 8000 ped., 1874, Wallis s.n. (BM).
Polytrichadelphus cuspidirostrum (Schimp.) Broth., Nat. Pflanzenfam. 1(3): 683. 1905. Polytrichum cuspidirostrum Schimp. ex Müll. Hal., Nuovo Giorn. Bot. Ital. n. s. 4: 16. 1897. Syntypes: Bolivia. Sin. loc., 1885, Mandon s.n.; Cochabamba, prope Choquecamata, Junio 1889, Germain.
Polytrichadelphus grossidens Müll. Hal. ex E. Britton, Bull. Torrey Bot. Club 23: 489. 1896. Catharinea grossidens (Müll. Hal. ex E. Britton) Müll. Hal., Nuovo Giorn. Bot. Ital. n.s. 4: 13. 1897. Type: Bolivia. Near Yungas, 4000-6000 ft. 1885, Rusby 3159.
Polytrichadelphus integrifolius Müll. Hal. ex E. Britton, Bull. Torrey Bot. Club 23: 490. 1896. Catharinea integrifolia (Müll. Hal. ex E. Britton) Müll. Hal., Nuovo Giorn. Bot. Ital. n. s. 4: 14. 1897. Type: Bolivia. Unduavi, 10000 ft., Oct 1885, Rusby 3159a.
Polytrichadelphus magellanicus (Hedw.) Mitt., J. Proc. Linn. Soc. 4: 97. 1859. Polytrichum magellanicum Hedw., Sp. Musc. Frond. 101. 20. f. 1-2. 1801. Type: Fretum Magellanicum. Report for the tropical Andes questionable.
Polytrichadelphus mitis Herzog, Hedwigia 67: 267. 1927. Type: Bolivia. Hacienda Simaco, am Weg nach Tipuani, ca. 1400 m, 1920, Buchtien.
Polytrichadelphus peruvianus Broth., Hedwigia 45: 275. 1906. Type: Peru. Rio Huallaga, an Felsen des Cerro de Escalero, 1400 m, Ule 2356.
Polytrichadelphus pseudopolytrichum (Raddi) G. L. Sm., Bryologist 79: 521. 1976 [1977]. Catharinea pseudopolytrichum Raddi, Mem. Mat. Fis. Soc. Ital. Sci. Modena, Pt. Mem. Fis. 18: 343. pl. 4: f. 3. 1821. Type: ?
Polytrichadelphus juniperaceus Müll. Hal., Gen. Musc. Frond. 168. 1900. Type: ?
Polytrichadelphus rubescens (Mitt.) G. L. Sm., Phytologia 18: 403. 1969. Polytrichum rubescens Mitt., J. Linn. Soc., Bot. 12: 622. 1869. Type: Ecuador. Andes Quitenses, Jameson.
Polytrichadelphus rubiginosus Mitt., J. Linn. Soc., Bot. 12: 610. 1869. Syntypes: Colombia. Antioquia, Jervis; Peru, Ruiz et Pavon; Huanaco provincia supra saxa, Herb. Hook. Andes Novo-Granatenses, in collibus prope Bogota (9600 ped.), Weir 211.
Polytrichadelphus rubiginosus var. patulidens Broth., Bot. Jahrb. Syst.56 (Beibl. 123): 22. 1920. Type: Peru. Prov. Tasma, Dep. Junin, Berge westlich von Huacapistana, Steppe mit eingesprengien Sträuchern, auf Erdblößen, 3400-3500 m, Weberbauer 2211.
Polytrichadelphus subrubescens (Thér.) G L. Sm., Phytologia 18: 403. 1969. Polytrichum subrubescens Thér., Rev. Bryol. Lichénol. 9: 6. f. 1. 1936. Type: Ecuador. Environs de Quito, 2800 m, Benoist 4658.
Polytrichadelphus trianae (Müll. Hal.) Mitt. f. cuspidata Herzog, Beih. Bot. Centralbl. 27: 357. 1910. Type: Bolivia. Unduavi, 3300 m, Dezember 1907, leg. O. Buchtien.
Polytrichadelphus umbrosus Mitt., J. Linn. Soc., Bot. 12: 610. 1869. Type: Chile. Chili, San Gavan, in umbrosis ad terram, Lechler 2205 (NY). Reported for Bolivia and Peru.
Polytrichadelphus valenciae (Müll. Hal.) Paris, Index Bryol. 994. 1879. Catharinea valenciae Müll. Hal., Linnaea 42: 468. 1879. Type: Venezuela. 1855, Fendler 73.