4 VoL. 30 | No.7 
BULLETIN 
OF THE 
TORREY BOTANICAL CLUB 
JULY, 1903 
A Preliminary Enumeration of the Grasses of Porto Rico 
By GrorGE V. Nasu 
This enumeration is based mainly upon the material in the 
herbarium of the New York Botanical Garden. The collections of 
Heller, Underwood and Griggs, Wilson and Goll are there fully 
represented, and those of Sintenis partially so. A few species, of 
which we have not seen specimens, have been admitted upon the 
authority of monographers. Further explorations of the island 
must add more species, and it is hoped that this enumeration may 
serve as a help in such further exploration. That this work may 
be facilitated, it has been deemed advisable to incorporate analyt- 
ical keys to the tribes, genera and species. This enumeration 
credits the island with 10 of the 13 grass tribes, 37 genera, and 
75 species and varieties, among them g hitherto unknown. 
Key to the Tribes 
A. Spikelets falling from the pedicel entire, naked or enclosed in bristles or a bur-like 
involucre, or immersed in the internodes of a readily disarticulating rachis, 1- 
flowered, or if 2-flowered the lower flower staminate (perfect in /sachne) : in- 
ternodes of the rachilla of the spikelet very short, not measurable. 
Spikelets round or somewhat dorsally compressed : hilum punctiform. 
Flowering scale and palet hyaline, thin, much more delicate in structure than 
the thick-membranous to coriaceous empty scales. 
Spikelets unisexual. Tribe I. MAYDEAE. 
Spikelets in pairs, one sessile, the other pedicellate, the former perfect, 
the latter sometimes perfect, often with a staminate flower, or fre- 
quently empty, abortive or wanting. Tribe IJ. ANDROPOGONEAE. 
Flowering scale, at least that of the perfect flower, similar in texture to the 
empty scales, or frequently thicker and firmer, never hyaline and thin. 
[The preceding number of the BULLETIN, Vol. 30, No. 6, for June, 1903 (30: 
319-368), was issued 11 Je 1903. ] 
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