ROBINSON AND BARTLETT. — PLANTS FROM GUATEMALA AND MEXICO. 49 
widely separated and not at all confluent. The segments are also 
pe sade opposite in P. pubescens, whereas in P. hispidulum they 
are alter 
en guatemalense Bartlett, n. sp., perenne 6 dm. altum 
simplex vel ramosum ; internodiis glabris lateraliter compressis, acie 
ad folii axillam versus canaliculatis ; foliorum vaginis equitativis pilo- 
sis (praecipue juxta margines et ad ligulae basin) quam internodiis aut 
brevioribus aut longioribus margine brunneo-scareosis ; ligula 2.5 mm. 
longa textura marginibus vaginarum simili ; laminis lineari- lanceolatis 
10-15 mm. latis 6-15 cm. longis apice acutis basi rotundatis vel sub- 
cordatis utrinque dense pilosis; spicis 1-3 sessilibus inter se 2.5-3.5 
em. distantibus 3-6 cm. longis ; rhachi angusta glabra vel scabriuscula ; 
pedicellis minute hispidulis ; spiculis geminatis altera breviter altera 
longius pedicellata, geminis secus rhachin in seriebus duabus alternis ; 
spiculis suborbicularibus 2.1 mm. longis 1.9 mm. latis glabris albican- 
tius viridibus antice planis postice valde convexis; gluma inferiore in 
spiculis geminorum superioribus suborbiculari apice rotundata quam 
spicula 6-plo breviore, in spiculis geminorum inferioribus longiore 
eccentrica late ovata obtusa vel acutiuscula ; gluma_ secunda membra- 
nacea quam spicula paulo breviore 5-nervata, nervis juxta marginem 
anastomosantibus ad apicem in mucronem perbrevem terminantibus ; 
gluma tertia membranacea quam secunda longiore 3 (—5)-nervata ; 
gluma quarta paleaque cartilagineis obscure nervatis ; staminibus sty- 
lisque ut in speciebus generis reliquis. — A swamp at Gualan, Depart- 
ment of Zacapa, Guatemala, January 20, 1905, C. C. Deam, no. 427 
(type, in hb. Gray). P. guatemalense is a member of Fournier’s genus 
Dimorphostachys. Following his arrangement of the group, the affinity 
of the new species is with Dimorphostachys Schaffneri Fourn., D. 
variabilis Fourn., and D. Ghiesbreghtii Fourn. Of these, only dD. 
Schaffneri is represented 3 in the Gray Herbarium. It may be at once 
distinguished from P. guatemalense by its glabrous foliage and larger’ 
— ovate spikelets, acute at the apex. D. variabilis and D. Ghiesbreghtii 
both have pubescent spikelets, whereas those of P. guatemalense are 
perfectly glabrous. 
SrreprocuartTa Soprroana Hack. Noteworthy among the plants 
collected by Mr. C. C. Deam in Guatemala is a specimen of the anom- 
alous South American genus Streptochaeta. The genus consists of two 
species, and in its spirally arranged (not distichous) flower-scales forms 
@ unique exception among the genera of grasses. When the generic 
affinity of Mr. Deam’s plant was discovered, it became evident that the 
species might be identical with the Ecuadorian S. Sodiroana A 
portion eal the apecimen was sent to Professor Hackel, who has kindly 
