172 ANALES DE LA SOCIEDAD CIENTÍFICA ARGENTINA 



simus. Folia laxa v. conferta subilla to-linearia spinescentia. 

 Flores parum numerosi, sessiles, acrogeni. 

 Genus FabianaeR. «£P. proximum, sed habitu totospinescenti- 

 h orrid o Strongylomatum, calvéis lobi va I de subulato-elongatis, 

 seminibus cristulato-alatis eximie distinctum. 



405. Pantacantha Ameghinoi Speg., n. sp. 



Diag. Perénnis, ramis elongatis subang ulosis pal lidis v. pulveru- 

 lentis tolis sublaxe foliosis; foliis priman' is subulato-linearibus 

 rigidis praelongts spinescentibus patentissimis glabris v. pulve- 

 rulentis, secundariis ad axillas primariorum fasciculatis bre- 

 vioribus pubescenti-pulverulenlis mucronato-spinosis ; floribus 

 ad apicem ramulorum axillarium saepias solitariis sessilibus, 

 calycis lobis triplo tubo longioribus , corollae glabrac tubo lobos 

 ca lijemos saepius parum superante, lobis corollinis reflexis, 

 staminibus in parte dimidia infera pubescentibus, stylo non 

 exerto. Capsula calyce non acérelo amplexa lobis calycims duplo 

 breviore, valvis coriaceis lignicoloribus; semina badia glabra. 

 Hah. In aridis glareosis secus Rio Chico, aut. 1898 (C. A.), nec 



non prope Lago Mustera, Febr. 1899 (>'. illin). 

 Obs. Frutex dense intricato-ramosus (20-40 cm alt.), ramis 

 rectis v. flexuosissubgracilibus (2-3 mm erass.), ligno albido, 

 cortice lenui, in vetustioribus sordide cinereo-nigrescente, in 

 junioribus albido-lutescente tectis, glabris v. in innovationi- 

 bus laxe breviterque pulverulento-pubescentibus. Folia pri- 

 maria patentissima fere ad angulum rectum, subligneo-rigida 

 anguste linearía subtrigona (15-35 mm long. = 1-1,25 mm 

 lat.) ad epiphyllum convexula v. obsoletissime subimpresso- 

 canalicuiata, ad bypophvllum obtuse carinato-convexula, ñer- 

 vo primario crasso a limbo angustissime marginiforme utrin- 

 que sulco longitudinal! - separato, a basi ad apicem sensim 

 attenuata atque in mucrone tereti longiusculo (3-4 mm long.) 

 acutissimo producta, lignicoloria v. pallide viridia, glabra v. 

 vix pruinuloso-pulverulenta, secundaria fasciculata minora 

 breviora molliora (5-15 mm long.), mucrone excepto, viridia 

 atque densiuscnle pulverulento-villosula, pilis breviter ramu- 

 losis crispí; lis. Flores in ramulis breyibus (5-20 mm long.) 

 axillaribus ad basin innovntionum acrogene solitarii erecti 

 sessiles, foliis ramulorum supremis oppositis v. suboppo- 

 sitis fere calyculati; calyx tubulosus glaber, tubo cyatboideo- 



