86 
REPORT ON BOTANY, MDCCCXLI : 
open ; dense tubes, of a deep red colour, are seen at the edge, 
and irregular tubes towards the middle, which are rather 
enlarged towards the upper part, and partially entwined with 
each other, and are seated on a mucus granular material. 
This substance constitutes the stroma of the pustule. A 
tissue of cylindrical, simple and ramified, very much matted 
together, fibres, is next produced. The disease terminates 
with the falling oJff of the leaves. It originates in the air 
holes of the leaf, in the form of a mucus granular material. 
The author attributes the cause to the moisture, which im- 
pedes the process of respiration. He concludes by saying, 
That the disease is a heterogeneous generation. 
The air holes (or organs of respiration) of the author are 
a layer of large cells. The author confesses, that the stomates 
are closed up even in the youngest leaves ; but is of opinion, 
that the air can penetrate nevertheless. We quite agree 
with the author in his concluding sentence, but this is a sub- 
ject of general physiology and pathology. 
M. Lucas has found humin in the Uredo segetum ; Einhof 
found the same substance, but did not recognize it as humin. 
Braconnot separated humin from the spiroids of Agaricus 
atramentarius, Bull ; and this substance, indeed, seems to 
prevail in many of these lower plants. Annal. d. Phar- 
macie v. Wohler and Liebig, vol. xxxvii. p. 90. 
MONSTEOSITIES. 
M. DE Lafont, Baron von Melicoeq, describes several modifi- 
cations of the Linaria vulgaris, in the Annal. d. Scienc. Natur. 
S. II., vol. xiv. p. 255, which may be compared with the great 
collection of such modifications which M. Pr. Batzeburg has 
published. They were collected at Cambrai and Arras, and 
are, — 1. Corolla with two lips, two spurs, equal or unequal; 
one of the flowers had six filaments, of which two were 
shorter than the others. 2. Corolla with two lips, three 
spurs, the central one longer ; of pretty frequent occurrence. 
3. Corolla with two lobes, three long equal spurs ; of rare 
478 
