343 
Zea canina, as grown at. Cambridge by Professor Watson, was ten 
feet tall, and suckered greatly ; as grown by Harshberger, at Phila- 
delphia, it was but five feet tall, and tillering is neither noted nor 
figured. Moisture seems to develop height, aridity to dwarf. 
When weeds, the great robbers of moisture from land, are allowed 
to develop freely in a cornfield, a moist spot will frequently bear 
corn of the normal height, while a neighboring drier hillock yields 
only dwarfed and stunted specimens. On the other hand some 
varieties seem to remain dwarf under all conditions observed. The 
tallest forms are recorded from hot and moist tropical regions, but 
So also are low-growing varieties. 
Contributions to American Bryology.—VIII. 
. 
By EL LizApetu G. BRITTON. ® 
A REVISION OF THE GENUS BRUCHIA, WITH DE- 
SCRIPTIONS OF TYPES, AND ONE NEW SPECIES. 
(PLATES 213-217.) 
BRUCHIA Schwegr. Suppl. 2: 91 (1824). 
PHASCUM Schreb. De Phasco Obs. (1770) in part. 
SPORLEDERA Hampe, Linnza, 279 (1837). 
The genus Bruchia was founded by Schwegrichen in 1824 for 
8. flexuosa, which had previously been described under Phascum 
from Specimens sent by Muhlenberg. The type species, therefore, 
's American, and the genus reaches its greatest development in 
North America, only two European species being so far known. 
Several have been described from Central and South America, 
and three from South Africa. 
Miller in his Synopsis Muscorum, 1849, recognized 7 species, 
of which four were American, and subdivided the genus into two 
S€ctions: : 
= Spelary Hpe. (B. Beyrichiana, B, palustris, B. brevipes). , 
. (B. flexuosa and var. minor). 
_ In the first section he placed the subacaulescent species, and 
M the second the taller, stemmed species with exserted capsules 
and long necks, 
