The North American Species of Lasiacis
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THE NORTH AMERICAN SPECIES OF LASIACIS. By A. S. HITCHCOCK. INTRODUCTION. Lasiacis is one of the few genera of grasses, excepting bamboos, that have woody culms. It was long included in the allied genus Panicum, from which it is well distinguished by the woody culms, the general habit, and the technical characters of the spikelet, es- pecially the shape of the fruit, the oblique position of the spikelets on the pedicels, and the woolly tips to the glumes and lemmas, these tufts of wool having suggested the generic name. Some of the species creep on the floor of the forest and some form a tangled mass of branch- ing culms, while the majority form strong central canes which clam- ber up through shrubs or over the margins of woods for several meters. The genus consists of 15 species, all confined to tropical America, one species reaching subtropical Florida. DESCRIPTION 01 THE GENUS AND SPECIES. V* . LASIACIS (Griseb.) Hitchc. Panicum section Lasi&cis Griseb. FL Brit W. Ind. 551, 1864, Five species are included in the section: P. Aivaricatum, P. sloanei, P. titnatum, P. com- pact urn, f. martinicense. Grisebach gives a satisfactory diagnosis of the sec- tion. Lasiacis Hitchc* Contr, U. S. Nat Herb. 15: 16.1910, The designated type is Panicum divaricatum L. DESCEIPnON. Perennial, shrubby, often climbing grasses with much branched culms (her- baceous and simple in L. procerrima)9 flat, often slightly petiolate blades, and open or somewhat contracted panicles terminating the main culm and primary branches, reduced panicles terminating the secondary, often fascicled branches. Spikelets subglobose, ovoid, or ellipsoid, placed obliquely on their pedicels, the glumes and sterile lemma broad, abruptly apiculate, papery-char taeeoust shin* In jr. often black at maturity, many-nerved, glabrous, or lanose at the apex only. First glume rarely over one-third the length of the spikelet, somewhat iuflaled-ventricose. Second glume and sterile lemma subequal, about a a long as the fertile lemma, or the glume slightly shorterf the lemma inclosing a mem- bra naceous pa lea and sometimes a staminate flower f rarely a second sterile lemma present* Fertile lemma white, bony-indurate, obovoid, obtuse, the mar- gins inrolled, inclosing the edges of the indurate palea, both lemma and palea 13 14 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. bearing at the apex In a slight crateriform excavation a tuft of woolly hairs, the palea concave below, gibbous above, the apex often free at maturity. All the species of Lasiaoia have woody culms except L. procenrima. The splkelets differ from those of Panieum in the bony obovoid fruit, pubescent at the apex, the palea concave below and gibbous above. KKY TO THE SPECIES, Cmlms erect, simple, herbaceous; blades as much as 40 cm. long and 5 cm. wide, deeply cordate-clasping 1, L. procerrima. Culms much branched, woody; blades mostly less than 20 cm, long, narrowed at base or somewhat cordate. Main stem prostrate, the fertile shoots prostrate, ascending, or erect. Blades lanceolate, mostly less than 5 cm. long; fertile shoots strongly dorsi ventral, mostly prostrate g, L. rugelii. Blades linear-lanceolate, about 10 to 12 era. long; fertile shoots ascending or erect from a decumbent base, not dorsiventral. 3. L< grisebachii. Main stem clambering, or much branched and forming a tangled mass. Ligule noticeable, brownish, about 2 mm. long. Blades glabrous beneath, scabrous on both surfaces, elongate, more than 10 times as long as wide; plants not forming a strong central clambering cane. , 4. L* oaxacensis. Blades puberulent beneath, glabrous or scabrous above, less than 10 times as long as wide; plants forming a strong central clambering cane 5, L. ligrulata. Ligule Inconspicuous, hidden within the mouth of the sheath, rarely as much as 1 mm. long. Plants not high-climbing, decumbent and rooting at base, forming a tangled mass, with no strong central cane; splkelets clustered toward the ends of the branches 6. It* rhizophora. Plants high-climbing, forming a strong central cane; splkelets not clus- tered toward the ends of the branches. Blades glabrous on both surfaces, often more or less scabrous* (See lu ruscifolia, this rarely with glabrous ovate-lanceolate blades.) Main culm papillose-hispid; lateral flowering branches glabrous; panicles small and narrow 7. X* leptostachya. Main culm (except sometimes the young shoots) glabrous. Blades narrow, usually 3 to 4 mm., sometimes 5 mm, wide, 8 to 10 cm, long 8* t, harrisii. Blades more than 5 mm, wide, if as much as 10 cm, long* Panicle few-floweredt 5 to 10 cm, long; branches strongly zigzag, the branchlets strongly divaricate or reflexed; blades nar- rowly lanceolate* firm, mostly less than 1 cm, wide (some- times wider on vigorous shoots) 9. L. divaricata. Panicles many-flowered, usually 15 to 25 cm. long or more on the primary branches; branches straight or arcuate* not zigzag; blades mostly over 1.5 cm, wide. Splkelets globose, about 3 mm, long, 10* L, globosa. Splkelets lanceolate-ellipsoidal, 3.5 to 5 mm. long. Splkelets 4*5 to 5 mm. long, on short stiff appressed pedi- cels; blades oblong-ovate or elliptic-lanceolate, 11. I*, sloanet* Splkelets 3.5 to 4 mm. long, on flexuous spreading pedicels; blades lanceolate or narrowly-lanceolate, IB. L* patentiflora. HITCHCOCK AND CHASE—NORTH AMERICAN GRASSES, 15 Blades pubescent on one or both surfaces (sometimes glabrous in L> ruscifolia). Blades narrowly lanceolate, averaging 8 to 10 times as long as wide; panicle large and open; spikelets 4 to 5 mm. long. 13. L, sorghoidea. Blades ovate-lanceolate or elliptic, sometimes lanceolate, often more or less cordate-clasping; panicle often compact, or at least the branches commonly compactly flowered; spikelets 3 to 4 mm, long. Sterile lemma 1 14. L, ruscifolia. Sterile lemmas 2 15, L. anomala* 1. Lasiacis procerrima (Hack.) Hitchc. Panicum proeerrimum Hack. Oesterr. Bot Zeltschr, 51: 431. 1901. "Cos- tarica : Inter frutices ad fluvium Tlliri prope La Verbena et Alajuelita (Pittier nr. 8819)-" Haekel states that this is "KIne ausgczelchnete Art der Series: Lasiacis Benth. et Hook, Gen. III. p. 1103." Lasiacis procerrima Hitchc, Proc. Biol. Soc. Washington 24:145,1911. Based on Panicum proeerrimum Hack. DESCRIPTION, Culms several in a clump, rarely single, succulent, somewhat woody at base but not perennial, erect from a thick woody rootstock, simple, as much as 4 meters high and 1 cm. thick, glabrous, glaucous; sheaths usually overlapping, glabrous or rarely pubescent; ligule inconspicuous; blades narrowly lanceolate, 15 to 40 cm, long, 2 to 5 cm, wide, deeply cordate-clasping, the lobes overlap- ping, gradually acuminate at apex, glabrous and glaucous, rarely pubescent, the basal lobes sometimes dilate; panicles open and much branched, as much as 1 meter long, the branches naked below, finally widely spreading, the lower in whorls, as much as 40 cm. long, the main axis smooth, the branchlets and pedicels scabrous; spikelets scattered, 3 to 4 mm. long, ovoid or elliptic. DISTRIBUTION. Banks and open woods, central Mexico to northern South America. SINATJOA : Colomas, Rose 1687, TEPIC : Tepic, Palmer 1921 in 1892. JALISCO : Rio Blanco, Palmer 535 in 1886. Guadalajara, Pringle 1732, 11760. COLIMA : Al%ada, Hitchcock 7085. MICHOACAN : El Ocote, Langlaasti 540. VEHACBUZ : CArdoba, Fink in 1893; Amer* Or. Nat. Herb. 596, Orizaba, Hitch- cock 6385. Mirador, lAchmann 305, 313. Veracruz, Qaleotti 5717. Huita- malco, Liebmann 308, La Loja, Liebmann 309. CHIAPAS: Ocuilapa, Nelson 3055. GUATEMALA: Chinantla, Seler 2405. Cubilqultz, Tiirckheim 1028, 8781. El Palmar, Kellerman 6247, Oenagullla, Heyde & Lu$ 3906. Cob&n, Tiirck- heim 2486. Guatemala City, Hitchcock 9067; PopeTtoe 737. Secoyocte, Cook & Qriggs 119. Secanqulm, Goll 43. NICARAGUA : Jlnotepe, Hitchcock 8694. COSTA RICA : La Verbena, Tonduz 8819, El General, Pittier 12057. San Jos6, Hitchcock 8445; Jim4nez 886. Puntarenas, Hitchcock 8572. Cafias Gordask Pittier 11011. Alajuela, Jimenez 532. 16 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM, PANAMA : Corozal, Pittier 6774. Frljoles, HitcJtcock 8393- Gatfln, Hitchcock 7984, El Boquete, Hitchcock 8283, Taboga Island, Hitchcock 8087, Pedro Miguel, Hitchcock 7961. COLOMBIA : San Andres de la Sierra, Pittier 1645. Santa Marta, Smith 117. VENEZUELA: Without locality, Fendler 2429, Caoma, Jahn 314, EXPLANATION OF PLATA 10.—LaalacLs procerrima. Specimen from El Boquete, Panama, Hitchcock 8283 (U. B. Nat Herb, DO, 946902)- Natural Btze. 3, Lasiacis rugelii (G rlseb,) Hitchc. Panicum rugelii Griseb. Cat. PL Cub, 233, 1866. " Cuba occ; In f rutlcetis montlum pr. Matanzas (Rug. 188)." Grisebach describes the plant as climbing, because Rugel's label had upon it " scandens." Lasiacis rugelii Hitchc, Bot Gaz, 51: 302, 1911. Based on Panicum rugelii Griseb. DESCRIPTION* Culms much branched, prostrate, the main culms slender, mostly about 2 mm., sometimes 2,5 mm. thick, appressed hlspidulous, the sterile shoots prostrate, dorslventral, the leaves strongly distichous, approximate, the fertile shoots sometimes ascending toward the end; sheaths overlapping, hlspidulous, villous on the margin and around the summit; ligule inconspicuous; blades lanceolate or oblong-lanceolate, 2 to 5 cm. long, 4 to 12 mm. wide, hlspidulous or puberu- leut on both surfaces; panicles few-flowered, usually not over 5 cm. long, the few branches spreading, the axes pubescent, scabrous on the angles; spikelets 5 mm. long, DISTRIBUTION. Rich thickets, western Cuba, Yucatan, and San Luis Potosl. SAN LUIS POTOSI: San Dieguito, Palmer 151 in 1904. RJo de las GalHnas* Purpus 5438. QUINTANA Roo: Lake Chlchankanab, Oaumer 23685. CUBA: Sierra de Anafe, WUson 11449, Valestina, Wright 3465. San Antonio, Hitchcock 176. Isle of Pines, Britton & Wilson 14860. Without locality, * Reed. EXPLANATION OF PLATE 11,—Lasiacis rugelii. Specimen from Valestlna( Cuba, Wright 8465 (U. S. Nat. Herb, no. 975684), Natural ate. 3. Lasiacis grisebachii (Nash) Hitchc. Panicum grisebachU Nash, Bull. Torrey Club 35: 301, 1908. The designated type is from Madruga, Cuba, Britton d Shafer 758. Nash gives the specific name because Grisebach1 refers Wright's no.