190 CHRIST. 



Dryopteris, in spitc of the sacrifice of personal opinions and in spite 

 of being obliged to diseard nanies tliat have been in constant use for a 

 century and which are known to all botanists. 



JSTowhere else is the tyj)e of Nephrodium witli anastomosing veins so 

 diversified as in the Diiiippines. There are in the Pliilippines fornis 

 with very narrow pinna3, and sonie special characters are found in the 

 species of this region niore often tlian in tliose of other parts of the 

 worhl. These characters are: Pinna? attenuated toward their ba.ses, 

 tht! lower ones defiexed, tlie pinnae degenerating into auricles at the l)ase 

 of the frond^ sometimes abruptly, sometimes gradually. In otlier equa- 

 torial regions species with these characters are ratlier rare. In tropical 

 America, Dryopteris sagittata (Sw.) is ahnost the only Imown species 

 of the group where the frond is abruptly reduced at the base, the lower 

 pinnae being represented by auricles, and D. refracta (Fiscli. & Mey.) 

 is one of the rare examples of a species with deflexed pinnse. The Ma- 

 layan region offers tlie most frequent examples of species presenting 

 tlie two last cliaracters, for example D. sagittifoUa (Blmne) of Java, 

 but even in tlie Malayan region sucli species do not approacli in number 

 tliose of tlie Philippines. 



There is in the Pliilippines a tendency to "insular" reduced types 

 wliicli is ratlier interesting. These reduced types elsewliere are rare, 

 and abnormaL Tlie irregularity and reduction of the fronds and even 

 tlie dimorphism of tlie fertile fronds is normal in Dryopteris canescens 

 (Blume) as found in the Pliilippines, and D. glandulosa lias analogous 

 tendencies. Tliese variations do not as yet appear to be constant, and 

 they offer some subspecies and varieties of doubtful value, wliich are 

 discussed later under the two above species. In the Arcliipelago more- 

 over are analogous variations in otlier genera, for example tlie singularly 

 stunted forms that are grouped under Leptochilus heteroclitus (Presl) 

 {Acrostichum fiagelliferum Wall.), and some species of Pteris, sucli as 

 P. ensiformis Burm., and P. heteromorpha Fee. In the West Indies, 

 Cuba, J amaica, Porto Eico, Santo Domingo, etc, analogous insular f orms 

 are foimd in Polystichum, Fadyenia, Sagenia and especially in Dryopteris 

 reptans (Gmel.) which tliere offer multiple reduced forms. I am sure 

 that the very prolonged isolation of tliese arcliipelagoes plays some role 

 in tlie occurrence of tliese variations, althougli it is not possible at present 

 to specify just wliat this influence is. 



Tlie wonderful variations of Dryopteris canescens, which are foimd 

 in otlier parts of Malaya (Celebes) only as rarities, but which are 

 developed in the Philippines into a bewildering series of forms, appear 

 to me to tlirow some new light on the "aberrant forms" of the old 

 scliool of pteridologists. By the variations of Dryopteris canescens, 

 which present an unbroken and insensible transition from a true Neph- 

 rodiuiii to a plant entirely achrosticlioid as to tlio sori, tlie affinity of 



