EXPOSURE ON LENGTH AND BREADTH OF LEAVES. 335 
These differences, though they also show a distinctly larger 
flower in the leaf-mould, are too small to be of much practical 
importance. 
LITERATURE CITED. 
STAHL.—Jenaisch. Zeit. Bd. xvi., 1882, p. 102. 
» Bot. Zeit., 1880. 
n Sitz. Jenaisch. Gesellsch., 1882. 
Vorkens.—Jahrb. d. k. k. Botan. Garten, Berlin, Bd. iii., 1881. 
» ‘Flora ZEgypt.-Arab. Wüste.” Berlin, 1887. 
TscuiRcH.— Pringsheim's Jahrbuch, Bd. xiii., 1882. 
» Linnea, Bd. xlii., 1881. 
ScHenck.— Bibliotheca Botanica, Heft 1 (Cassel). 
35 Ber. d. deut. Bot. Ges. Bd. ii., 1884. 
LuBrock.—' Flowers, Fruits, and Leaves.’ 
Durovxk.—Ann. Sci. Nat., Bot. ser. 7, t. v. 1885, p. 311. 
SoRAUER.— Bot. Zeit., 1878, p. 1. 
5 Wollny’s ^ Parichianson a. d. Geb. Agricultur,' Bd. ix. 
Vesave & VIET.—Ann. Sci. Nat., Bot. ser. 6, t. xii., 1882, p. 167. 
WiEsner.—‘ Biologie d. Pflanzen,’ pt. ii., Wien, 1890. 
Costantin.—Ann. Sci. Nat., Bot. sér. 6, t. xvi., 1883. 
Ann. Sci. Nat., Bot. sér. 6, t. xix., 1885. 
7 Ann. Sci. Nat., Bot. ser. 7, t. iii., 1886. 
Scorr ELLr0T.—Gardener's Chronicle, Dec. 6th, 1890. 
Ross.—Bot. Centralblatt, Bd. xvii., 1884, p. 78. 
v. HónsxEL.—Wollny's * Forschung. a. d. Gebiet. d. Agricultur Physik,’ 
Bd. ii. 
KrauscH.—Inaugur. Dissert., Leipzig, 1887. 
N OACK.— Pringsheim's Jahrbuch, Bd. xviii., 1888. 
GREVILLIUs.— Bot. Centralblatt, Bd. xxxvi., 1888. 
SCHWENDENER.—Abhandl. d. kön. Akad., Berlin, 1882. 
HEINRICHER.— Pringsheim’s Jahrbuch, Bd. xv., 1884. 
GirTAv.—Nederl. Kruidkund. Archief, Ser. 2, Deel iv. 
FLEISCHER.— Bot. Centralblatt, Bd. xxii., 1885, p. 356. 
Jonow.— Pringsheim's Jahrbuch, Bd. xv., 1884. 
SCHIMPER.—Bot. Centralblatt, 1884. 
Sacus.— Lectures on Physiology,’ Engl. transl. 
Horrman.—Bot. Centralblatt, Bd. xxv., 1886, p. 359. 
ScHoLrz.—Cohn's Beiträge, Bd. iv. p. 292. 
39 
