HITCHCOCK AND CHASE—TROPICAL NORTH AMERICAN PANICUM. 493 
Spikelets expanded at maturity by the enlarged sterile palea, 
usually blunt. 
Panicle branches not racemose; blades scarcely mide than 
their sheaths; sterile palea conspicuously enlarged. 
Spikelets 3 mm. long, congested; panicles,dark purple... 58. 
Spikelets not over 2.4 mm. long; panicles green or pale. 
Panicle branches spikelet-bearing or branchlet 
bearing along the upper half or toward the 
BIGOT US) Gals sa a ee ne ee 57. 
Panicle branches branchlet-bearing throughout their 
lenctimonmeanly sOn.s cece. ces ole 56. 
Panicle branches subracemose, the spikelets secund; blades 
at least 5 mm. wide; enlarged sterile palea not con- 
spicuous. 
Blades narrowed toward the base.............-.----+-.- 54. 
Blades cordate or truncate at base. 
Spikelets 2 mm. long; panicle branches erect or 
FOS St) Saye US irl a pt ea shes an 55. 
Spikelets not over 1.6 mm. long, usually less; panicle 
branches spreading or ascending. 
Panicles one-third to half as wide as long; spike- 
lets not conspicuously secund, somewhat 
irregularly disposed; blades cordate- 
WSeCCIEYS) alia seagate ays TERA NSS tT De 
Panicles rarely one-fourth as wide as long; spike- 
lets conspicuously secund and regularly 
disposed. 
Culms as much as 2 meters long; panicles 
— 
POCO SONCTAs LOM eA ie eh eee eye 51. 
Culms not over 1 meter long; panicles 5 to 
Loven lone toe Sis eee ees lean 52. 
49. Panicum longum Hitche. & Chase. 
Panicum longum Hitche. & Chase, Contr. 
U.S. Nat. Herb. 15: 111. 1910. 
DISTRIBUTION. 
Swamps, State of Veracruz. The only 
collections known are from near Jalapa, 
Pringle 8195 (the type) and Schiede & Deppe 
674 (Haile Herb.). 
P. cupreum. 
P. hians. 
P. exiguiflorum. 
P. laxum. 
P.. stevensianum. 
. P. boliviense. - 
P. Milleflorum. 
P. pilosum. = 
Fic. 68.—Distribution of P. longum. 
50. Panicum polygonatum Schrad. 
Panicum polygonatum Schrad. in Schult. Mant. 2: 256. 1824; Contr. U. 8. Nat. 
Berb. 15: 112. 1910. 
DISTRIBUTION. 
Swamps and moist soil, Mexico to Paraguay. The type ar from Die 
Veracruz: Cordoba, Bourgeau 1662 in part. 2 
GUATEMALA: Sepacuité, Collins & Goll 08, Cook & ‘nage 530. ‘Cubilquite 
Tiirckheim 7797, 8795. Puerto Barrios, Kellerman 5114. 
Honpuras: San Pedro Sula, Thieme 781, 5578, 5587 in part. 
? 
