TAB. 338.
ARTHRATHERUM OBTUSUM, Nob.
A R T H R A T H E R U M , Pal. B e au v .— Confer, supra, p. 5o.
ARTHRATHERUM OBTUSUM, Nob.
Aristida obtosa, Del., Flor. Mgypt. , p. 3i ; tab. x3, fig. a.
Stipagrostis obtosa , Nees ab Es., in Linncea, vol. 7, p. 293. — Kunth, Enum., vol. is p. 198.
Dense caespitosum; cauliculis sterilibus confertissimis, foliosis; caulibus floriferis parcis. Nodis
glabris. Foliis involutis, setaceo-filiformibus, obtusiusculis, glabris; vagina apice barbato-ciliata.
Glumee valvis subasqualibus, trinerviis, lineari-lanceolatis, glabris, convolutione quasi subulato-acu-
miuatis. Flore breve stipitato. Palea externa (apice obtuse biloba, in sinu aristata, immediatim cum
ai'ista articulata) glabra, laevigata. Aristae {parte indivisa recta) laciniis lateralibus nudis, lacinia media
a basi ad i /3 nuda inde ad apicein plumosa subduplo brevioribus.
Gramen perenne, speciebus affinibus humilior; caudice brevi, irregulariter ramoso. R adix e fibris crassiusculis elongatis
simplicibus tomentellis subfasciculatis constans. Cauliculi steriles aggregati, breves, conferte foliosi, ad basin squamosi
subbulbiformes, caulibus fiorigenis crebriores. C aules 3-6 pollices longi (adjecta inflorescenda), pro cespids densitie parci,
erecti v. subdiffusi, geniculati (rarius recti), simplices, filiformes, teretes, levigad, obsolete striatuli, medulla fared, uni-v.
bi-nodi, nodulis constricd et saepe colore atroviolaceo tined, basi foliosi et vaginis vesdd; internodia vaginis longiora; ard-
culus summus nunc longius nunc brevius exsertus. F olia glaucescenda, rigida, crassiuscula, plus minusve arcuata v. varie
flexuosa, ecarinata, nervosa (sub lente), extus scabra (papillulis acudusculis oculo nudo inconspicuis conspersa), intus
lanulosa, ad vaginam articulata; radicalia conferta, i/3- i 11/2 pollicem longa; folia caulina conformia foliis radicalibus illisque
modo breviora modo longiora. V agin.® infim® aphylle, submembranacee, striate, ovato-v. oblongo-lanceolate, mucronat*
v. cuspidulate, plerumque glabrae. V agin® foliorum radicalium complicate, distiche imbricate, persistentes, chartacee,
straminee, nervöse, dilatate, marginibus lalo-membranacee, apice rotundato-bilobulate et dense ciliate, ore annulo setula-
rum brevissimarum barbulate, secus apicem margine remote ciliolate, cetero glabre. V agin® foliorum caulinorum tubuloso-
involute, arete, herbacee, elongate, scabriuscule, apice truncato-v. rotunda to-bilqbula to dense ciliate v. ciliolate, ore
barbula annulari setularum brevissimarum instructe, reliquo glabre. L igula nulla. P anicula 2-4 pollices longa, e spiculis
7-25 composita, oblonga, laxa, simplex, erecta (v. forsan sub anthesi nutans). Caulibus macrioribus occurrit panicula depau-
perata, racemiformis, e spiculis 5-7 composita. R hachis scabra (setulis aculeoliformibus, oculo nudo inconspicuis), condnua,
filiformis, subsemi-teres, plus minusve flexuosa. R amuli solitarii, alterni, distichi, subcapillares, flexuosi, scabri, spiculas
2-7 pedicellatas racemosim dispositas geteiltes; superiores inferioribus gradatim breviores. Pkdicelli solitarii v. gemini,
alterni, disdehi, scabri, inequales (plerumque gluma breviores), capiliares, apice incrassati. Gluma 3 i /2-5 lineas longa,,
straminea v. violascens, persistens, flore (preterraissa hujus arista) subtriplo longior. Valv® submembranacee, subnaviculares,
subequilonge, trinervie (nervis filiformibus, lateralibus supra valve medium cum nervo medio paululo crassiori confluen-
tibus), extus scabre (papillulis acutis, oculo nudo inconspicuis), facie glabre levigate, dorso nervo medio carinulate, basi
amplexatiles ac intruse, apice truncato nunc mutice nunc mucronulate. Valva interior exteriori paululo altius inserta,
subbrevior et parum angusdor, ceteris conformis, intus ad basin rndimento lineari obtuso glabro basi callosa adnato floris
alterius instructa. F los cum sdpitulo suo (pretermissa arista) circiter sesquilineam longus. Stipitolus palea externa triplo
brevior, cardlagineus, crassus, turbinatus, setulis albidis dense sericeus, apice circumbarbatus (villis inequalibus, majoribus
dimidiam longitudinem palee externe equantibus), basi subulato-angustatus. Palea externa (generis more tubuloso-involuta,
tenuiter trinervia, ecarinata, chartacea, demur» rigida, subcoriacea) albida, levigata, glabra, cuneato-oblonga, apice
rotundato-biloba, longe aristata. A rista decidua, violascens, setaceo-subulata, 8 - 1 5 lineas longa, supra basin geniculata et
trifurcata; pars indivisa brevis, filiformis, nuda, sublevigata, erecta, non contorta, canaliculata; lacinie laterales capiliares,
nude, scabre, recte, divergentes; lacinia media robustior, recta, a basi ad circiter i /3 nuda scabra, iude ad apicem villis
elongatis albidis dense plumosa. Palea interna (generis more minima, membranacea, hyalina, enervia, involuta, ecarinata,
glaberrima) obovata, obtusissima, integerrima. Squami)l®-htpogvn® gemine, glaberrime, submembranacee, palea interna
longiores, sublanceolate, acuduscule, enervie. Stamina 3 , supra basin sdpiluli pisdlligcri inserta. F ilamenta capillaria.
rA B , 538.