632 LOASACE^. Mentzelia. 



times few, rarely solitary : styles usually united into one. Fruit 

 mostly capsular or succulent, crowned with the limb of the calyx. 

 Seeds anatropous, either numerous, few, or rarely solitary, not aril- 

 late, usually with more or less fleshy albumen. Cotyledons flat or 

 plano-convex. — Herbs (all American), sometimes climbing or twin- 

 ing, mostly armed with bristly stinging hairs, which secrete an acrid 

 juice, and rough with a barbed pubescence. Leaves alternate or 

 opposite, lobed or toothed, without stipules. Flowers commonly 

 large and showy, mostly yellow. 



1. MENTZELIA. {Plwnier?) Linn. ; Lam. ill. t. 425. Juss. in ann. 

 mus. 5. p. 24. 



Mentzelia & Bartonia, Nutt., Pursh, ^c. — Acrolasia, Presl. 



Tube of the calyx cylindrical or clavate ; the limb 5-parted. Petals .5, or 

 sometimes 10, plane, spreading or erect-sjireading, mostly somewhat ungui- 

 culate : sestivation convolute. Stamens indefinite (30-200 or more), or rarely 

 10-20 ; five or more of the exterior filaments often dilated, or petaloid and 

 sterile, the others filiform and often in 5 or more phalanges : anthers oval, 

 innate. Ovary coherent with the tube of the calyx, with 3 (rarely more?) 

 parietal placentae : ovules numerous or reduced to a single one on each pla- 

 centa : styles 3, filiform, connate so as to appear simple and often spirally 

 twisted, but usually divisible to the middle : stigmas simple, minute. Cap- 

 sule crowned with the lobes of the calyx, 1 -celled, 3- (or more ?) valved at 

 the summit, 3-many-seeded. Albumen thin or almost none : cotyledons 

 broad and flat. — Branching herbs, more or less rough and tenacious with 

 rigid barbed hairs. Leaves alternate, coarsely-toothed or sinuate-pinnatifid. 

 Flowers mostly sessile, 1-3 together, golden yellow, or rarely whitish. 



We are constrained to adopt the suggestion of Hooker «fe Arnott (Bot. Beechey, 

 suppl. p. 343 ; see also Hook. f. Bor.-Am, 1. p. 222,) and to refer Bartonia, Nutt. 

 as well as Acrolasia, Presl. to Mentzelia. In his manuscript notes recently com- 

 municated to us, Mr. Nuttall establishes the genus Trachyphytum, to include 

 Bartonia albicauUs, Hook, and other species which have no inner series of petals 

 or dilated filaments, and 20 or more cubical seeds arranged in a single series on 

 each placenta ; while his Bartonia is distinguished by its double rows of com- 

 pressed or winged seeds, and by having a portion of the filaments dilated or 

 changed into petals. But Trachyphytum, of which some species have wholly 

 the habit of the large-flowered Bartonias, is only distinguished from Mentzelia by 

 the rather more numerous seeds ; and Bartonia micrantha. Hook, t^ Arn., which 

 has 5 petaloid filaments, has a S.seeded capsule. Could the Bartonia of Nuttall be 

 retained as a genus, we fear that the name would require to be changed ; as the 

 Bartonia of Muhlenberg and Willdenow (1801) is much older, and was published 

 two years before Centaurella, Miehx. (1803) 



§ 1. Seeds 3-9, often minutely striate: filaments all nearly equal and filiform, 

 or 10 of them longer and more or less dilated : flo^ccrs expanding in direct 

 sunshine. — Eumejvtzelia. 



