Ptendoph5ten. 679 



centic, and amphivasal steles in the same strobilus axis in L. cari- 

 natum, and all types but the amphivasal in L. phleginaria and L. 

 variuni. 



L. BiUardieri is the most constant in its stelar structure, with 

 a type of stele so characteristic as to make the species almost re- 

 cognizable by the transverse section of the stem. The Organization 

 of the strobilus is distinctly radial. The structure of the stem con- 

 sists of several radiating bands of xylem with phloem groups be- 

 tween them. 



L. verticUlatum has generall)'^ parallel-banded arrangeraent of 

 Stele, although the radial stele has been considered the prevailing 

 type in epiphytic species. 



All attempts to place the species of Lycopodium in definite 

 categories based on the character of the stele are extremely uncer- 

 tain (Jones, Holiowa y, Wigglesworth, Boodle), since there 

 are exceptions in some species and even exceptions in different 

 parts of the same stem in some species. If the character of the 

 Stele is in any way dependent upon varying conditions, its use in 

 phylogeny must recognize this fact. The invesiigation confirms the 

 idea that the radial arrangement of the stele, retained persistently 

 by the root, is probabl}'' the most primitive stem arrangement, 

 from which most known stems have departed. Jongmans. 



Maxon, W. R., Studies of tropical American Ferns. 5, 

 (Contrib. United States Nat. Herb. XV^I. 4. p. 391— 425. PI. 11 — 23. 

 Textf. 8-10. 1914.) 



This contribution contains 9 different articles. 



1. The American species of Oleandra, p. 392—398. A kej'- to 

 the american species of this genus and an enumeration with syno- 

 nymy, notes on distribution and on published figures. Several new 

 species are described: 0. guaternalensis, O. lehmannn, O. decurrens, 

 O. panamensis, O. trinitensis and O. costaricensis. Altogether eleven 

 species of Oleandra are known at present from tropical America. 



2. Notes upon Polypodium duale and its allies, p. 398 — 406. 

 Polypodiuni duale belongs to a small group, tvhich has been 

 regarded b}'" several writers in the past as constituting a separate 

 genus, Xiphopteris. It is 'in many cases difificult to distinguish be- 

 tween P. duale and its allies, followed by a description, accom- 

 panied by füll synonymy, lists of illustrations, notes on distribution, 

 historical and systematical details. FoUowing species are considered 

 as belonging to the same group with P. duale: P. myosuroides 

 Swartz (Fl. 11, fig. A, B, textf. 9), P. delitescens Maxon {Grammitis 

 myosuroides Schkur, not Polyp, myosuroides Swartz) illustrated on 

 Fl. 12, fig. A, B, and in Textf. 10, P. stricfissimum (Hook.) Hieron., 

 P. sajfordii Maxon (P. ininimum Brack, not Aubl.) and P. wittigia- 

 num (Fee et Glaz.) Christ. P. duale itself is illustrated in Texf. 8. 

 P. schenkii Hieron. must be excluded from this group. 



3. New species of Polypodium, p. 406—411. P. hyalinum from 

 Costa Rica, a member of the group of P. trichornanoides. P. blepharo- 

 <5?e.s from Costa Rica and Guatemala, belongs to the same group and 

 is most nearly allied to P. daguense Hieron. and P. taenifolium ]enm.a.r\.. 

 P. cooki Underw. et Maxon from Guatemala also of the P. tri- 

 chornanoides group, but wholly unlike any of the American species 

 thus far described. P. perpusillum (Fl. 13 A) collected in ßrazil 

 and named by Christ P. setosum Mett. (= P. micropteris Q. Chr.). 



