sæpe 2-3 minoribus; stigmatibus 8; bacca obovata; seminibus undulato-marginatis majusculis.

Var. B. MONTANA: subinermis; stramineo-setosa.

Along the Canadian River east of the Llano Estacado, and on that plain. Var. B. near Albuquerque. - Joints 2-3 inches in diameter, in B. larger; longer spines 1-2 inches long. Fruit short, pulpy, sweet. Seed 2 lines in diameter, with a very sharp irregularly wavy or twisted border. - The var. B. seems to unite the common O. Rafinesquii with this form.

O. STENOCHILA, E. & B. 1. c. : prostrata; articulis obovatis ; pulvillis remotis stramineo-setosis, superioribus solum armatis; aculeis singulis albidis patulis, 1-2 minoribus deflexis sæpe adjectis; bacca obovata clavata; seminibus crassis anguste marginatis.

Zuni, Western New Mexico. Joints 4 inches long and 3 wide; spines 1-1 inches long. Fruit green or pale red, very juicy, 14 or sometimes even 24 inches long. Seeds quite peculiar, regular, much thicker in proportion than those of most other Opuntia, and with a very narrow edge. — Another form, with smaller and rounder joints, more spines, smaller fruit, but similar seeds, was found in the same neighborhood.

All the forms described above have fibrous roots. The following are principally characterized by their bulbous or tuberous roots, but can hardly be otherwise distinguished from the forms already described. Both are found westward of the range of O. Rafinesquii proper, and may be considered as subspecies, the peculiarities of which are readily propagated by seeds.

O. MACRORHIZA, E. in Pl. Lindh. part 1: prostrata, sæpe adscendens, radicibus tuberosis; articulis obovato-orbiculatis perviridibus; pulvillis subremotis rufo-setosis, superioribus solum armatis; aculeis singulis validis sæpe variegatis patulis, 1-2 gracilioribus deflexis subinde additis; alabastro acuminato; petalis circiter 8 sulphureis basi miniatis; stigmatibus 5; bacca obovata basi clavata, umbilico lato; seminibus subregularibus compressis minoribus.

- -

Sterile, rocky places on the Upper Guadalupe River, in Texas: fl. May and June. Roots in young specimens fusiform, in old ones enlarged to fleshy tubers, sometimes 2 or 3 inches in diameter. Joints 21-3 inches long, the leaves and bristles the same as in 0.

Rafinesquii. Flowers 3 inches in diameter. Fruit green or pale purple, smaller and sweeter than that of O. Rafinesquii.

O. FUSIFORMIS, E. & B. 1. c. : subprostrata; radicibus elongato-fusiformibus; articulis orbiculatis; pulvillis setas elongatas virescentifuscas gerentibus,. plerisque vel solum superioribus armatis; aculeis 2-3 gracilibus albidis deflexis seu patentibus; floribus minoribus; stigmatibus 8; bacca ovata; seminibus majusculis subregularibus.

Kansas and Nebraska, in the regions of the Cross-Timbers, from the Canadian to the Big Bend of the Missouri. - Roots elongated tubers -1 inch in diameter; joints about 3-4 inches long; spines an inch. or a little more in length, slenderer and paler than in O. Rafinesquii. Flowers 2-2 inches in diameter. Seed 2 lines wide. This plant has been distributed by me under the name of Opuntia bulbosa.

17. O. FUSCO-ATRA, E. in P. R. R.: diffusa; articulis orbiculatoobovatis tuberculatis; pulvillis subremotis magnis griseo-tomentosis, inferioribus solum inermibus; setis numerosis robustis longiusculis fuscis; aculeis subsingulis robustis fusco-atris suberectis, altero breviore deflexo sæpe adjecto; floris flavi ovario conico pulvillos 12-18 fulvo-villosos et fusco-setosos gerente; stigmatibus 5.

Sterile places in prairies, west of Houston, Texas: fl. May. The stout brown, or above almost black spines, and the thick bunches of unusually stout brown bristles on the small joints, give this plant a very distinct appearance. Joints 2-3 inches long; pulvilli 6-9 lines apart; bristles 2-3 lines long; spines 1-1 inches long, the lower one, when present, about half as long, but hardly less stout. Flower nearly 3 inches in diameter; ovary an inch long, rather slender, its pulvilli covered with long grayish-brown wool, and the upper ones with a few bright-brown bristles.

18. O. VULGARIS, Mill.: diffusa, prostrata; radice fibrosa; articulis obovatis seu suborbiculatis crassis læte seu pallide viridibus plerumque inermibus; foliis ovatis cuspidatis fere adpressis; pulvillis subremotis parvis subimmersis setas paucas abbreviatas virescenti-stramineas gerentibus; aculeis rarissimis singulis robustis variegatis suberectis; alabastro subgloboso obtuso; ovario clavato pulvillis sub-10 stipato; petalis sub-8; stigmatibus 5; bacca obovata clavata; seminibus regularibus crassis crasse marginatis.

From the southeastern coast of Massachusetts to Georgia and Florida; apparently only in the low countries east and southeast of the Alleghany Mountains, generally not far from the sea-coast: fl. May and June. Joints 2-4 inches long and 2-2 in diameter, rather thick and fleshy. Leaves 2-2 lines long, generally appressed, only in

very vigorous specimens more patulous: spines, when present, less than 1 inch long, but stout. Flower about 2 inches in diameter, pale yellow. Seed 2 lines in diameter. It seems to be well distinguished from O. Rafinesquii (which grows only west of the Alleghanies) by the smaller size, paler color, small pulvilli, usually the absence of spines, the smaller flower, with all the parts less numerous, and especially by the short, thick, and more or less appressed leaves.

§ 5. Pubescentes: erectæ seu procumbentes: articuli pubescentes :

folia minuta: aculei subnulli.

*Flaviflora.

19. O. MICRODASYS, Lehm.: erecto-patula; articulis oblongis obovatis seu orbiculatis pubescentibus læte viridibus; foliis minutis; pulvillis confertis inermibus lanam flavidam setasque numerosas gracillimas flavas gerentibus.

Only south of the lower Rio Grande, near Rinconada, etc. Plant 2-4 feet high; joints 2-3 inches long, 1-2 wide; pulvilli - ↓ of an inch apart.

20. O. RUFIDA, E. in B. C. R.: erecto-patula; articulis late-obovatis seu suborbiculatis pubescentibus; foliis longe acuminatis; pulvillis confertis setas rufidas graciles numerosissimas gerentibus inermibus; floris flavi ovario obovato pulvillis numerosis instructo; stigmatibus 7 in capitulum congestis.

Common about Presidio del Norte, on the Rio Grande: fl. May. Stem 2-4 feet high, much branched; joints 3-6 inches long; leaves 2 lines long. Flower 2 inches in diameter, with 40-50 pulvilli on the ovarium. Apparently near O. microdasys and O. puberula; distinguished from the former by the rounded joints, larger leaves, and red-brown bristles; from the latter by the entire absence of spines, and of the purplish spot which in that species surrounds the pulvillus. Further investigations are necessary to decide about these closely allied forms, as about most species of this intricate genus.

**Rubriflora.

21. O. BASILARIS, E. &. B. 1. c.: humilis; articulis obovatis seu triangularibus glaucescentibus pubescentibus e basi proliferis; foliis minutis; pulvillis subconfertis fulvo-villosis setas gracillimas demum numerosissimas fulvidas et subinde aculeolos setiformes caducos gerentibus; floris purpurei ovario obovato pulvillis plurimis instructo;

stigmatibus 8 in capitulum congestis; bacca obovata late umbilicata (sicca?); seminibus magnis crassis subregularibus.

On Williams's River, the Colorado, and the Mojave, and down to the Gila: fl. April and May. - Habit very different from any other of our Opuntia; the stout obovate or fan-shaped joints (5-8 inches long) originate from a common base, forming a sort of rosette. Leaves only one line long, 4-6 lines apart; pulvilli red-brown, somewhat immersed. Flower about 2 inches in diameter; ovary with 40-60 pulvilli. Fruit apparently dry, thereby approaching the next section. Seed 3 lines in diameter, 2 lines thick.

Mr. Schott has observed, on the dividing ridge of the California mountains, west of the mouth of the Gila, and again in the Santa Cruz Valley, Sonora, a very similar but suberect species, 3 feet high, spineless, inclined to assume a purplish hue, which he seems to have confounded with O. basilaris. Can it be 0. rufida, or is it an undescribed species ?

§ 6. Xerocarpeæ: diffusa: articuli suborbiculati vel tumidi: aculei plurimi bacca sicca aculeolata: semina eburnea, magna, plerumque latissime marginata.

Articuli compressi suborbiculati.

22. O. HYSTRICINA, E. & B. 1. c.: diffusa; articulis obovato-orbiculatis; pulvillis subconfertis setas pallidas rutilasve gerentibus, omnibus armatis; aculeis 5-8 superioribus validis elongatis angulatis seu tortis patulis vel deflexis, inferioribus 5-7 gracilioribus radiantibus; bacca ovata aculeolata, umbilico planiusculo; seminibus maximis.

West of the Rio Grande, to the San Francisco mountains. - Joints 3-4 inches long; pulvilli 5-6 lines apart, unusually large; longer spines 1-3 and even 4 inches long, brownish; lower radiating ones white, 49 lines long. Fruit an inch long; upper pulvilli with 4-6 bristly spines. Seeds 3 lines in diameter, among the largest in this

genus.

23. O. MISSOURIENSIS, DC. (Cactus ferox, Nutt. Gen.): prostrata; articulis obovatis vel suborbiculatis tuberculatis; foliis minutis ; pulvillis subconfertis stramineo-setosis, omnibus armatis; aculeis 510 exterioribus radiantibus setiformibus albidis, 1-5 interioribus robustis albidis seu rufescentibus; floris flavi intus aurantiaci ovario obovato vel subgloboso spinuloso; stigmatibus 5-10 viridibus; bacca spinosa, umbilico plano; seminibus magnis irregularibus.

Var. a. RUFISPINA, E. & B.: articulis orbiculatis; aculeis interioribus 3-5 validis fuscis; bacca ovata.

Var. B. PLATYCARPA, E.: articulis obovato-orbiculatis; aculeis interioribus subsingulis validis fuscis; bacca depresso-globosa late um

bilicata.

Var. y. MICROSPERMA, E.: articulis aculeisque præcedentis; bacca ovata breviter aculeolata; seminibus minoribus anguste marginatis.

Var. 8. SUBINERMIS, E.: articulis elongato-obovatis, pulvillis subremotis inferioribus inermibus, superioribus aculeos paucos breves gerentibus.

Var. . ALBISPINA, E. & B. : articulis late obovatis ; aculeis 6–12 omnibus albis gracilioribus; bacca ovata.

Var. . TRICHOPHORA, E. & B.: articulis ovatis; pulvillis confertis ; aculeis 10-18 setiformibus (in articulis vetustis numerosioribus) capillaceis flexuosis; bacca ovata; seminibus maximis.

From the Upper Missouri to the Canadian; principally occupying the western plains, but also on the mountains towards Santa Fé and west of it. The last-mentioned variety (which I would consider a distinct species, were it not for the var. albispina, which seems to unite it with the others) has been found only on the mountains near Albuquerque all the other forms occur on the Upper Missouri, and a. and e. also on the Canadian. Other and intermediate forms of this variable but nevertheless well-characterized species will no doubt be found in the wide territory inhabited by it. It flowers in May and June. Joints 2-4, rarely 4-6 inches long, and 2-3 inches wide, light green leaves 1-2 lines long; larger spines 1-1, rarely 2 inches long, in 8. not more than 3-6 lines long. Flowers 2-3 inches in diameter, with short green stigmata forming a compact head. Fruit 1-14 inches long, with shorter or longer spines, and a rather shallow umbilicus. Var. B. has a remarkably large flat fruit. Seed generally about 3 lines, but in y. only 2 lines, in diameter.

24. O. SPHÆROCARPA, E. & B. 1. c. : diffusa; articulis orbiculatis tuberculatis; pulvillis confertis stramineo-setosis plerisque inermibus, summis solum aculeos 1-2 deflexos patulosve majores gerentibus, adjectis sæpe 1-3 brevioribus; bacca globosa vix aculeolata; seminibus mediis.

Mountains near Albuquerque, New Mexico.-Joints 3 inches in diameter, strongly tuberculated; pulvilli 4 or 5 lines apart; spines 6-12 lines long, reddish-brown, often single or 2 or 3 together, with