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28 FIELDIANA: BOTANY, VOLUME 28
Panicum vinaceum is related to P. cervicatum Chase, which has
very large, diffuse panicles as much as 40 cm. long, the branches
glabrous or nearly so at the base, and larger spikelets, 7-8 mm. long.
Ichnanthus acuminatus Swallen, sp. nov.
Perennis; culmi robusti, 170 cm. alti, basi decumbentes, infra
nodos dense pubescentes; vaginae internodiis longiores summum
versus carinata, hirsutae, collo dense pubescentes; ligula membranacea
3 mm. longa; laminae 15-20 cm. longae, usque ad 2 cm.
latae, lanceolato-acuminatae, pubescentes vel pilosae; paniculae
ca. 30 cm. longae, 10-20 cm. latae, oblongae vel pyramidatae, ramis
adscendentibus basi dense pubescentibus vel pilosis; spiculae 3.4-
3.5 mm. longae; gluma prima 2-3 mm. longa, acuta vel subacuminata,
3-nervis, carina scabra; gluma secunda et lemma sterile aequalia,
5-nervia, scaberula; fructus 2.8 mm. longus, glaber, alls angustis,
obtusis, 0.5-0.7 mm. longis.
Perennial; culms rather coarse, erect from a decumbent base, as
much as 170 cm. high, densely pubescent below the nodes; sheaths
mostly longer than the internodes, somewhat keeled toward the summit,
densely pubescent on the collar, hirsute to nearly glabrous on
the back; ligule membranaceous, about 3 mm. long; blades 15-20
cm. long, as much as 2 cm. wide, firm, lanceolate-acuminate, usually
pubescent or pilose on both surfaces; panicle about 30 cm. long,
10-20 cm. wide, oblong or pyramidal, the branches verticillate,
ascending or the lower spreading, densely pubescent or pilose in the
axils; spikelets 3.4-3.5 mm. long, the lateral ones short-pediceled,
appressed; first glume 2-3 mm. long, broadly triangular, acute or
sub-acuminate, 3-nerved, scabrous on the keel; second glume and
sterile lemma equal, sub-acute, 5-nerved, scaberulous; fruit 2.8-3
mm. long, slender, glabrous, the wings 0.5-0.7 mm. long, narrow,
rounded above.
Type in U.S. Nat. Herb., no. 1,911,659, collected along stream in
Gran Sabana, between Kun and L'aduara-paru', in valley of Rio
Kukena'n, south of Mount Roraima, state of Bolivar, alt. 1065-1220
m., October 1, 1944, Julian A. Steyermark 59086. Also collected on
Gran Sabana, between Santa Teresita de Kavanayen northwest of
Rib Karuai, on large mesa, state of Bolivar, alt. 1220 m., 59371;
savanna bordering forest of Rib Karuai, between Santa Teresita de
Kavanayen and base of Ptari-tepui', state of Bolivar, alt. 1220 m.,
60335.
Ichnanthus acuminatus is related to/, verticillatus and /. ichnodes,
both of which have smaller spikelets; the former has broad thin
blades as much as 5 cm. wide, and the latter has narrower elongate
blades. True /. ichnodes is known only from Trinidad.
Ichnanthus duidensis Swallen, sp. nov.
Annuus; culmi decumbentes, 110 cm. longi, glabri; vaginae carinatae,
glabrae, internodiis breviores; ligula membranacea, ca. 0.5