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Revista de la Facultad 
233. Perezia sessiliflora Speg. (n. Sp.). 
Diag. Homqianthus; pererinis, dense caespitosa, ramis abbreviatis 
dense imbricato foliosis; foliis coriaceis glaberrimis anguste linea- 
ribus, non patentibus. sessilibus, postice in pericladio subscarioso 
intus longe gossypino-lanoso dilatatis amplexicaulibus, ápice sub- 
acutiusculis non v, vix mucronulatis, margine revolutis integerrimis, 
eapitulis solitariis inter folia suprema sessilibus, squamis ovato-lan- 
ceolatis integris spinuloso mucronatis, floribus 10-12, coroUis albis. 
Hab. Non rara in campis aridis glareosis prope Rio Santa Cruz, 
anno 1882 (C. S.) et prope Rio Deseado et Golfo San Jorge, annis 
1894-96 (C. A.). 
Obs. Caules perennes dense caespitosi, pulvinulos irregulares 
subhemisphaericos (10-25 cnt diam.) efficientes, ramis abbreviatis 
(1-2 cnt long.) dense imbricato-foliatis; folia linearla (8-i2mmlong. 
= i-r,5 mm diam.) coriacella rigidula glabra erecta subadpressa 
(nunquam divaricato-patentia) sessilia, deorsum in pericladio mem- 
branáceo subscarioso (5 mm long.=4-5 mm lat ) vaginanti-amplexi'- 
cauli integeirimo non auriculato 3-nerve dorso glabro intus laxe 
longeque gossypino villoso dilatata, ápice obtusiuscula v. acu- 
tiuscula non v. mucrone pallidiore brevissimo (non spinoso) or- 
nata, margine revoluta integerrima, in ramulis novellis viridia 
glaberrima, in vetustis persistentia arescenti-cinerea; capitula 10 12 
flora, solitaria (rarius bina) in ápice l amulorum inter folia suprema 
sessilia, campanulata (8-10 mm long.=6 ymmdiam.), squamis 10-15 
involucrata; squamae involucri 3-4-seriatae, externae breves i-co- 
stafo-subcarinatae, internae planae longiores (7 mm long. = 3 mm 
lat.) glabrae virides, margine integro non v. vix hyalino (rarius 
minutissime subfimbriato), ápice obtusae atque in mucrone non v. 
vix subspinoso plus minusve elongato (0,5-1 mm long.) productae; 
receptaculum non v. vix puberulum, obsolete alveolatum; flores 
10-12 bilabiati, ovariis linearibus angulosis (3 mm long. — 0,7 mm 
diam.) non v. vix papilloso-pulverulentis, pappi albi pluriserialis 
setulis tenuibus rectis dense minuteque denticulato-barbellatis, co- 
roUis albis (6-7 mm long.) ligula externa lata ápice coarctatula mi- 
nuteque 3-denticulata. 
Species nulla alia descripta accedens. 
234. Nassauvia Ameghinoi Speg. (n. sp.). 
Diah, Mastigophorus; fruticulosa ramosissima caespitosa, foliis 
remote imbricatis, patentim recurvis, minutis crassis coriaceis in- 
tegris, ventre convexis glabris 2 sulcatis, sulcis pubescentibus, dor- 
so adpresse sericeo-villosis, sessilibus, basi in vagina ápice utrin- 
que i-dentata, subscariosa amplexicauli dilatata; eapitulis apicalibus 
solitariis, sessilibus 5-floris corollis albis. 
Hab: Non rara in valleculis glareosis aridis prope Golfo de San 
Jorge, anno 1896 (C. A.). 
Obs. Rami primarii repenti-effusi, frustulis sordide cinerascenti- 
