202 



group must of necessity be more truly comparative and involve a 

 wider view than is usually to be required in most groups of pteri- 

 dophytes. But the fact remains, that there arc distinct groups, in- 

 habiting definitely restricted areas and comprising individuals in 

 close agreement in habital and foliage characters, which offer com- 

 paratively small but absolute differences from allied groups of in- 

 dividuals from other regions ; and it appears to the writer that, 

 unless reduction of the most sweeping sort is to be made, it is 

 undoubtedly the most logical proceeding to recognize these as 

 species and to designate them as binomials. The recognition of 

 svib-species implies or ought to imply the existence of specimens 

 snowing the transition from the typical form to the sub-specific 

 centre of variation. In two or possibly three instances among the 

 recently recognized " species" referred to above, such intermediates 

 seem to exist, and the writer hopes to discuss these later at greater 

 length ; but in the majority of cases intermediates (if existent at 

 all) have not found their way into herbaria, and the supposed 

 justification for the reduction practised by several American writers 

 appears to be contained in the fast disappearing fallacy that the 

 sum of the differences and not their constancy is the criterion for 

 specific segregation, — a logical pursuit of which principle would 

 lead by no very circuitous route to the treatment accorded the 

 group by Hooker and Baker. 



The plant here to be described is not associable specifically 

 with any described form. It may very appropriately bear the 

 name of one whose studies must necessarily prove largely instru- 

 mental in a final elucidation of this perplexing group. 



BOTRYCHIUM UNDERWOODIANUM sp. nov. 



Plant of large stature (3 dm.), to be placed between B. Jciiiiiaiii 

 and B. dccompositum of the ternatum group. Roots copious, stout, 

 cordlike, corrugate above, fasciculate from a short (l-2 cm.) under- 

 ground prolongation of the axis : common stalk short (about 2 

 cm.), bud densely covered with a compact growth of silky hairs ; 

 sterile division short-petiolate (5-10 cm ), 12-20 cm. broad and 

 nearly as long, commonly pentagonal in shape, tripinnate, the basal 

 pinnules of the lowermost lateral divisions usually much elongated 

 and again deeply pinnatifid ; ultimate segments relatively very 

 large, bluntly obovate or broadly spatulate, the margins evenly 

 and finely crenate-dentate with an occasional shallow lobation ; 

 texture slight, lesembling that of B. obliquni ; venation manifest : 

 sporophyl about 30 cm. long ; panicle rather lax, about 8 cm. long, 

 bipinnate ; sporangia large, sessile. 



Jamaica. — Type in the herbarium of the New York Botanical 

 Garden, Jenman collection. Co-type in the U.S. National Herbarium 

 (no 521 103). Of the several specimens collected by Jenman only 

 one is fertile. Other Jamaican specimens are : Underwood i~g and 

 2620, Ma.voii 1573, and D. E. Watt{\J. S. N. M. 520982). all from the 

 vicinity of Cinchona, altitude about 1500 meters ; and two speci- 

 mens in the herbariam of Capt. John Donnell Smith, communicated 



