1902] CURRENT LITERATURE 77 
green portions of the leaf. Thin albescent parts are due to a reduction in 
palisades and intercellular spaces. ‘The author finds a close relation to exist 
between chlorophyll development and leaf thickness, including the develop- 
ment of palisade cells; if chlorophyll stops abruptly in a variegated leaf, the 
thin part begins abruptly and palisades cease at once; if the chlorophyll fades 
out gradually, the leaf gradually becomes thinner and palisades gradually 
cease. These results and those of Rodrigue seem to throw doubt on Stahl’s 
theory that palisades are due to the direct influence of light, and relate them 
rather to the presence of active synthesis; the reviewer, however, has 
observed palisade cells in the albescent parts of many leaves. Timpe finds 
that albescent portions of leaves redden more than the green portions; this 
harmonizes well with Overton’s conclusions,™ since the white leaf parts are 
found to be rich in tannins and sugars, though poor in starch. 
Laurent,* discusses the origin of albescence in plants. There are two 
types, those coming from spores, and those that reproduce by seed e 
latter type is ordinarily thought to be not responsive to external buctous In 
Some situations plants which are commonly albescent have green leaves, and 
in other situations the reverse is the case. Laurent thinks that some enzyme 
intervenes to cause a modification in the distribution of the chlorophyll. 
Molisch * observed that Brassica oleracea acephala becomes albescent 
in cold greenhouses in winter, and becomes green again in summer, the 
whitening beginning in October and reaching its maximum in February. 
The author thus holds with Laurent that albescence may be affected by 
external factors. In the case of Brassica the author thinks that temperature 
is the factor involved, since warm greenhouse cultures do not show the ee 
phenomenon.— H. C. Cow es. = 
ITEMS OF TAXONOMIC INTEREST are as follews: F, STEPHANI (Bull. 
Herb. Boiss. Il. r:1141. 1g01) has segregated a new genus (Cuspidatula) of 
s from Anastrophyllum, the 4 species included belonging to the East 
Indian and Australian n region.— B. L. Rosinson (Rhodora 3: 270-276. age 
has published a synopsis of the North American species of Euphrasia,recog- 
nizing 7 species, 2 of which are new (Z. Williamsit from Mt. Washin ington oe 
and £. Randii from Mt. Desert.)— THEO. Horm (Ottawa Nat. 15 2175-183. 7 
Pls. 11-14. 1901) has described 3 new Canadian species : Gentiana belong- — 
. ing to § Crossopetalae.—S. B. ParisH (Proc. Calif. Aca Sat III. Bot.2:159-_ 
172. 1901) has revised certain troublesome species of Solanum of the S. Xanti_ 
and S. umbelliferum gro p, describing 3 new species and 4 new varieties, and 
- Biving detailed Secs of po deieeistiag HELGI JONSSON (Botanisk ’ -Tidsskrift — - 
MP5s. Igor) has published an account of the Rhodophyc eae as - 
, ee . - “Series of papers on the marine algae of Iceland, 2 new a 
BOT. Gaz. a7: 491. 1899. - *5 Bull. Soc. oe 39: 6-9. neste S 
— whe ch iorad 19: 32-34. Igol. : 
