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MAXON— STUDIES OF TROPICAL AMERICAN FERNS. 37 



Cuba, Porto Rico, and Guadeloupe.™ The Porto Rican material, indicated by Kuhn 

 as a distinct species under the manuscript name Aspidium krugii, has since been 

 described by the writer as Pohjstichum krugii; and with this has been associated the 

 Wright Cuban specimen. A reexamination of the whole series, however, fails to dis- 

 cover any stable characters by which the extremes of this variable species may be 

 separated. The most conspicuous character of the Porto Rican plant lies in the greatly 

 elongate linear caudate apex, as opposed to the broader and shorter apex of the Jamai- 

 can plant; but specimens intermediate in this and other characters occur, and it is 

 evident that situation and exposure must play an important part in determining 

 dimensions, form, and texture of individual plants. In Jamaica, according to Jenman, 

 the species occurs "in well-drained stony woods, on rocks and bowlders up to 1,000 

 feet or more." It was not observed by the writer. 



Jamaica: "Near Kingston, 7 ' Safford 9. Without locality, ex herb. Bot. Dept. 



Jamaica. Without locality, Purdie (E); Hart 181. 

 Porto Rico: Near Cayey, Sintenis 2240, 2240c. On the Adjuntas road, 7 miles 

 from Ponce, Heller 6095. Between Aibonito and Cayey, Mr. & Mrs. A. A. 

 Heller 536. Near Utuado, Sintenis 6274b. Bairoa (Caguas), Goll 342. 

 Cuba: Ingenio Soledad, near Cienfuegos, Santa Clara, Pringle 106. In crevices 

 of rocks, Los Portales de Guame, December 31, 1864, Wright, no. "F" (E). 



17. Polystichum struthionis Maxon, nom. nov. Plate 8. 

 Aspidium mucronatum Hook. Sp. Fil. 4: 9. pi. 216. 1862, not Sw. 1801. 

 Polystichum echinatum C. Chr. lnd. Fil. 83. 1905, not Polypodium echinatum Gmelin. 



1791. 

 The present species is described fully by Hooker and by Jenman and is well figured 

 by Hooker, on the basis of specimens from Jamaica, under the name Aspidium mucro- 

 natum. The true mucronatum of Swartz, however, is a form of triangulum, as stated 

 on page 28, and echinatum is its equivalent . Schkuhr appears to have first misapplied 

 the Swartzian name, figuring at the right of plate 29 C of bis Kryptogamische Gewachse 

 the species taken up later by Hooker under this name. Hooker's figure is much better 

 than Schkuhr's, and neither shows any especial resemblance to Sloano*s plate 36. 

 figure 4, the prototype of mucronatum and echinatum . With a series of Jamaican plants 

 at hand the misidentification is most obvious. 



The species is, so far as definitely known, confined to Jamaica; the additional 

 accredited range of Guadeloupe and Santo Domingo must be regarded as very doubt- 

 ful, in view of the invariable misapplication of the name mucronatum. Dependence 

 may be placed on Jenman's very full and accurate description, and Hooker's figure is 

 unmistakable. The species shows no approach to any other. The deeply serrate 

 form, mentioned by Jenman as bipinnatifid, was collected in Jamaica by the writer 

 only once (no. 1614) ; it appeared to have been induced directly by the unusually open 

 dry habitat. 



Jamaica: Highest slopes of John Crow Peak, altitude 1,650 to 1,800 meters, 

 Underwood 2442; Maxon 1316. Vicinity of New Haven Gap, altitude about 

 1,650 meters, Maxon 2660. Near Whitfield Hall, Maxon 1470. Clyde River 

 Valley, altitude 900 to 1,200 meters, Underwood 458, 2659; Maxon 1610, 1614. 

 NearMabess River, altitude about 1,200 meters, Harris 7596. Trail from 

 Cinchona to Morces Gap, altitude 1,500 meters, Underwood 322, 1207. Quashi 

 Hill, altitude 1,500 meters, Eggers 3763. Without locality, N. Wilson; Gil- 

 bert; Jenman; Hart 209. 

 Explanation of Plate 8.— Fig. A, middle portion of an ordinary frond, Clyde River Valley, 

 Jamaica, Underwood 4i8; B. middle portion of a large incised frond, same locality, Maxon 1614. Figures 

 A, B, natural size. 



18. Polystichum tridens (Moore) Fee, lime Mem. 74. 1866. 

 Aspidium tridens Moore; Hook., Sp. Fil. 4: 15. pi. 215. 1862. 



a Engler's Bot. Jahrb. 24: 112. 1897. Guadeloupe specimen not seen by the writer. 



