DR. SPRUCE ON THE TECUNDATION" OP GRASSES. 
5 
Without pausing to inquire how many grasses are practically 
diclinous, although apparently hermaphrodite, I may begin by 
speaking of the numerous tropical grasses (often conspicuous for 
their size and beauty) which have the sexes positively and per- 
manently separated, some being monoicous, others dioicous. 
Here, unquestionably, there can be no fertilization before the 
opening of the flowers. To render this plain, let us pass in re- 
view some of those grasses which have the male and female 
organs in distinct flowers. 
In gently flowing rivers of Tropical America grow many fine 
aquatic grasses, species of Luziola, Oryza, Leersia, &c. The follow- 
ing note is from my journal, under date December 1849, wheu 
threading in my canoe among the islands of the Trombetas. "This 
channel was lined on both sides by a beautiful grass (a species of 
Luziola) growing in deep water, and standing out of it 2 or 3 feet. 
The large male flowers, of the most delicate pink, streaked with 
deep purple, and with six long yellow stamens hanging out of them, 
were disposed in a lax terminal panicle ; while the slender green 
female flowers grew on the bristle-like branches of much smaller 
panicles springing from the inflated sheaths of the leaves that 
clothed the stem. As the Indians disturbed the grassy fringe with 
the movement of their paddles, the pollen fell from the anthers 
in showers," and would doubtless, some of it, attain the female 
flowers disposed for its reception. 
A parallel case to the above is that of the common maize {Zea 
Mays^ L.) where the male flowers are borne in a long terminal 
raceme or panicle, and the female flowers are densely packed on 
spikes springing from the leaf-axils. Here the male flowers 
must plainly expand before the pollen contained in their anthers 
can be shed on the female organs below, whether of the same 
or of a difl'erent plant. That there are frequent cross-marriages 
in maize is evidenced by the numerous varieties in cultivation 
in countries where it is a staple article of food, as in the Andes 
of Ecuador, where nine kinds, varying in the colour of the grain 
(through white, yellow, and brown, to black), in its size, con- 
sistence and flavour, are commonly cultivated, besides many 
others less generally known. 
In a Tripsacum (a tall grass that sometimes covers deserted sites 
in the plain and the lower Andes) the inflorescence is a long 
terminal spike, beset in its lower part with female, in its upper 
part with male flowers ; the former hidden in excavations of the 
VOL, III. 0 
