212 BOTANICAL GAZETTE [MARCH 
as it shows strong powers of readjustment in such highly specialized forms as 
succulent plants. The author concludes by saying that the air and not the 
soil relations are determinative for the above changes. This is in harmony 
with Kohl’s results on Tropaeolum. Brenner thinks that the phenomena 
which he observed are in a high degree purposeful, and that ene, physical 
explanations are very difficult at many points.— H. C. Cov 
ITEMS OF TAXONOMIC INTEREST are as follows: ARTHUR MINKs (Mém. 
Herb. Boiss. 22: 1-74. 1900) has published a full discussion and synopsis 
of the genus Umbilicaria.— WILLIAM R. Maxon (Proc. Biol. Soc. Washing- 
ington 13: 199, 200. 1900) has described a new Polypodium (P. hesperium), 
which is “the common form of the whole mountain region of the western 
described a new Dryofteris from Alaska.— P. A. RYDBERG (Bull Torr. Bot. 
Club 27: 614-636. 1900), in continuing his ‘Studies on the Rocky mountain 
flora,” has published an account of some of the smaller genera of Compositae. 
Those considered are Stenotus, formerly a section of Aplopappus, containing 
seven species, of which two are new; Stenotopsis, a new genus established on 
Aplopappus (Stenotus) linearifolius, and including also Aplopappus Sepanee 
interior ; Macronema, containing seven species, of which one is new; 
ranthus, a genus revived to include species formerly under Aplopappus, a 
more lately under Eriocarpum, and which is recognized as containing seven 
species, three of which are new; Pyrrocoma, with sixteen species, five of 
which are new; Ba/samorrhiza, with nine species, two of which are new; 
Thelesperma, with seven species, two of which are new; Hymenopappus, with 
eight species, four of which are new.—EpwarpD L. GREENE (Pittonia 
4: 159-226. 1900) has recently made some important contributions as fol- 
lows: A fascicle of new forms of Arnica contains twenty-four species; 
Gentianaceae are enriched by three new species of Gentiana, three of Swertia, 
and three of Frasera; the third of the ‘Studies in the Cruciferae” discusses 
certain species of Avadzs, describing seventeen as new, describes new species 
in Cheiranthus, Sophia, Thelypodium, Thysanocarpus, Draba, and Cardamine 
(4 spp.), expresses his conclusion as to the type of the genus Draéda, and estab- 
lishes a new genus (Aédra) upon what is known as Draba brachycarpa,; the 
second of the papers on “ Neglected generic types’’ brings to us FHlaler- 
pestes as a new genus established to include Ranunculus Cymbalaria Pursh, 
R. salsuginosus Pallas, and R. tridentatus HBK., Peritoma DC. to include 
certain species of Cleome (serru/ata, inornata lutea), Celome founded on 
Cleome platycarpa Torr., Carsonia founded on Cleome sparsifolia, and Alde- 
nella founded on .Polanisia tenuifolia T. & G.; eighteen new species are 
added to the genus Aséer, all but one of which are from the Rocky mountains; 
among the “ Corrections in nomenclature’ Oveostemma is substituted for the 
untenable Oveastrum Greene (containing certain species formerly referred 

