320 PLANTJE NOVJE THURBERIAN.E. 



their lamina less than a line long, ovate, sometimes appearing subcordate by the inflec- 

 tion of the margins of the claw at its summit, but when explanate it is found to be 

 ovate-spatulate, with a tapering base, the surface minutely veined. Filaments attaining 

 the length of half an inch, glabrous : anthers small, with no apparent connective. 

 Style resembling a filament, terminated by a minute and simple stigma. Ovary not 

 ribbed, angled, nor appendaged, ripening without much change, or any considerable en- 

 largement, into a thin and fragile hispid-scabrous utricle, H or 2 lines long, from which 

 the calyx-lobes fall, and which at length breaks in pieces irregularly. Seed filling the 

 cell, obovate, pointed at the hilum, smooth. Cotyledons thick, plano-convex ; radicle 

 short, acute. 



Botanists will recognize in this plant a very interesting addition to the tribe or sub- 

 order Gronoviece, composed of those Loasacece which have the ovules reduced to a 

 single one, suspended from the summit of the cell, and the seed destitute of albumen. 

 The present genus is especially remarkable for the very long-clawed petals ; from which 

 character the name is derived. It forms in some respects a connecting link between 

 Gronovia and Cemllia ; while the anthers are those of a Mentzelia. Professor Fenzl 

 would probably recognize the petals of Petalonyx as homologous with the inner series 

 of the perianth of Cemllia, unless, indeed, on comparing them with the stamens of the 

 latter genus, surmounted by petaloid tips, these slender petals were regarded as an ex- 

 ternal series of stamens transformed into staminodia. But I can draw no line of dis- 

 tinction between true petals and an external series of sterile, anantherous stamens, 

 alternate with and next within the sepals. 



EREMIASTRUM, Nov. Gen. Compositarum. 



Capitulum multiflorum, heterogamum, heterochromum ; fl. radii uniserialibus ligu- 

 latis fcEmineis ; disci tubulosis hermaphroditis. Involucri subbiserialis squamte lineari- 

 lanceolatse, laxee, sequilongee, foliacete, marginibus hyalinis fimbriatis alatse. Recepta- 

 culum hemisphsericum, nudum. Ligulae circiter 20, elongatse. CoroUte disci subcylin- 

 dricse, tubo proprio brevissimo, limbo 5-lobo. Styli rami plani, appendice brevissima 

 obtusissima. Achenia compressa ? hirsuta, binervia. Pappus in radio et disco con- 

 formis, brevis, duplex ; exterior e paleis 10 - 12 oblongo-cuneatis setoso-palmatifidis ; 

 interior e setis totidem rigidis scabris insequalibus, nempe, 5-6 paleas bis superantibus 

 corollce disci dimidio brevioribus, et 5 - 6 alternis minoribus. — Herba pumila, mono- 

 carpica, cinereo-hispida ; foliis alternis lineari-spathulatis ; ramis capitulum majuscu- 

 lum basi foliosum gerentibus ; ligulis albis. 



