/ 



ROBINSON AND BARTLETT. — PLANTS FROM GUATEMALA AND MEXICO. 49 



widely separated and not at all confluent. The segments are also 

 prevailingly opposite in P. pubescens, whereas in P. hispid 'alum they 

 are alternate. 



Paspalum guatemalense Bartlett, n. sp., perenne 6 dm. altum 

 simplex vel ramosum ; internodiis glabris lateraliter compressis, acie 

 ad folii axillam versus canaliculars ; 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 

 cm. 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 ; glama secunda menibra- 

 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 IK 

 Schaffneri is represented 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. I), variabilis and 1). Ghiesbreghtii 

 both have pubescent spikelets, whereas those of P. guatemalense are 

 perfectly glabrous. 

 v/ Streptochaeta Sodiroana 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 

 a 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 8. Sodiroana Hack. A 

 portion of the specimen was sent to Professor Hackel, who has kindly 



VOL. XLIII. — 4 



