mostly 6 lines, lower ones 6-10 lines, upper ones 8-15 lines long; central spine, if present, 12 - 15 lines long.

$ 3. Pentalophi.

23. C. BERLANDIERI, E. in B. C. R.: humilis, perviridis; caule diffuso subtereti articulato ramosissimo; tuberculis conicis 5-6-fariis; aculeis 6-8 setaceis brevibus radiantibus albidis, centrali singulo multo longiore fusco; floribus magnis; petalis angustis recurvatis ; seminibus tuberculatis.

On the Nueces, in Southern Texas: fl. May and June. - Stems 11 -6 inches long, one inch thick; radial spines 4-5 lines long, central one 6 - 12 lines long, toward the base of the branches shorter. Flower 2-4 inches long.

24. C. PROCUMBENS, E. in Pl. Lindh. 1850: humilis, perviridis ; caule diffuso subtereti 4-5 angulato articulato ramosissimo; aculeis 4-6 radiantibus albidis, centrali nullo vel singulo paullo longiore obscuro; floribus magnis; petalis obovato-spathulatis patulis seu subrecurvis; seminibus tenuissime verrucosis.

On the Rio Grande, below Matamoras: fl. May and June. Similar to the last; but more slender, 6-8 lines in diameter; radial spines 1-2 lines long, central one, if present, 2-3 lines long. Flower above 3 inches long.

25. C. TUBEROSUs, Poselger: e radice tuberosa tenuissimus, teres, sursum incrassatus, demum articulatus, 8-costatus; aculeis minutis setaceis, 9-12 radiantibus, centrali singulo longiore sursum adpresso; flore subterminali; seminibus minutis scrobiculatis.

Between Laredo and Mier on the Rio Grande. Tuberous root 1 inches thick. Stem above 4-8 lines thick; radial spines hardly 1 line, central ones 2-3 lines long. Seed smaller than in any other Echinocereus, 0.4 line long, with the tubercles confluent.

Subgen. 2. EUCEREUS. Caulis elongatus: fasciculi aculeorum steriles et florigeri similes: floris tubus elongatus, sæpissime aculeolis capillaceis munitus: stigmata pallida: semina lævia seu raro rugosa: embryo hamatus.

26. C. EMORYI, E. in Sill. Journ. 1852: prostratus; ramis adscendentibus 15-costatis; areolis confertis; aculeis setaceis rigidis flavis,

radialibus 40-50 stellatis, centrali unico longiore robustiore; flore flavo breviusculo; bacca aculeatissima; seminibus magnis lucidis.

On hills near San Diego, California, growing in thick patches.Stems several feet long; branches 6-9 inches high, 1 inches in diameter, Fruit very spinose, with seeds over one line in length.

27. C. VARIABILIS, Pfeiff. erectus, 3-4 angulatus; areolis remotis; aculeis 4-6 brevibus radiantibus, 2 - 4 interioribus validis elongatis inæqualibus divaricatis, centrali deflexo; flore magno albo nocturno; bacca coccinea aculeolata; seminibus magnis lævibus.

On the lower Rio Grande: fl. in May and June. - Well known from all parts of tropical America. Fruit 3 to 10 feet high, 2 inches in diameter; larger spines 12-18 lines long. Fruit 2-3 inches long, nearly 2 inches in diameter.

28. C. GREGGII, E. in Wisl. Rep. gracilis, e radice crassa napiformi erectus; ramis 3-6-angulatis, rufescentibus; areolis confertis ; aculeis e basi bulbosa abrupte subulatis brevissimis nigricantibus, radialibus 69, centralibus 1-2; floris elongati albidi tubo aculeolis capillaceis flexuosis munito; bacca sessili obovata apice rostrata; seminibus rugosis.

Var. a. CISMONTANUS: areolis elongatis; petalis latioribus.

Var. B. TRANSMONTANUS: areolis ovato-orbiculatis; petalis angustioribus.

From Western Texas to Sonora, and south to Chihuahua: fl. May and June. — Root a large fleshy tuber, sometimes 6 inches in diameter. Stems 2-3 feet high, 9-12 lines thick, usually 4- or 5-angled; spines 1 line long, very sharp; lower ones longer. Flower 6 or 8 inches long, 2-2 wide. Fruit 1-1 inches long. Seed 1-1 1 lines long.

Subgen. 3. LEPIDOCEREUS. Caulis elongatus: fasciculi aculeorum steriles et florigeri similes: floris tubus brevior squamosus: phylla numerosissima: stigmata pallida: semina lævia: embryo ha

matus.

29. C. GIGANTEUS, E. in Emory's Rep. 1848: erectus, elatus, parce erecto-ramosus, 18-21-costatus; aculeis 12-16 radialibus inæqualibus, centralibus sub-6 robustis basi bulbosis corneis basi nigris cæteros superantibus, infimo longiore deflexo; floribus subterminalibus albidis; bacca obovata demum 3 - 4-valvi.

From the Lower Gila north to Williams's River (better known

-

among western travellers as Bill Williams's Fork), and south into Sonora fl. May-July; fr. July and August. A now well-known plant to travellers and botanists, 30-50 feet high, 1-2 feet in diameter; central spines 1-2 inches long. The yellowish-white flower 34 inches long. Fruit 2-3 inches long, often pear-shaped, and opening with 3 or 4 irregular recurved valves.

30. C. THURBERI, E. in Sill. Journ. 1854: caulibus erectis vel adscendentibus pluribus elatioribus articulatis 13-14-costatis; aculeis 7- 15 gracilibus fusco-atris valde inæqualibus; ovario tuboque imbricato-squamato; bacca globosa magna.

Sonora, west of the Sierra Madre: fl. June and July. - Stems 515 from one root, 10-15 feet high, 4-6 inches in diameter; spines slender, flexible, from 5-18 lines long. Flowers 3 inches long, white. Fruit like a large orange, of delicious flavor.

Subgen 4. PILOCEREUS. Caulis elatus: fasciculi aculeorum steriles a floriferis tenuioribus longioribus distincti: floris tubus brevis squamosus phylla pauciora: stigmata pallida: semina lævia: embryo hamatus (in specie nostra !).

31. C. SCHOTTII, E. in B. C. R.: caulibus erectis vel adscendentibus pluribus elatioribus articulatis 4-7-costatis; areolis in articulis sterilibus remotis; aculeis brevibus robustis, radialibus 4-6, centrali unico; areolis in articulis floriferis confertis; aculeis 15-25 longioribus setaceis flexuosis e rubello cinereis; floribus carneis minoribus, tubo gracili decurvo; bacca parva.

Sonora, towards Santa Magdalena fl. July. Stems 8-10 from the same base, often growing in dense clusters, 8 or 10 feet high, with 24 articulations, 4 or 5 inches in diameter. Spines of the sterile part of the plant 3-4 lines long, on the fertile joints 1-4 inches long, pendulous, forming a reddish-gray beard, in which the flower (not 2 inches long) is somewhat hidden. Seeds large cotyledons hooked, exactly as in the last two species. This is evidently a Pilocereus, but with the seed of a true Cereus, thus reuniting the former with the latter.

Trib. II. ROTATÆ, Miquel.

Aphyllæ seu foliosa. Flores tubo abbreviato subrotati. Cotyledones facie versus hilum spectantes seminis lateri contrariæ (incumbentes).

IV. OPUNTIA, Tourn.

Ovarium sepalis subulatis caducis axillâ pulvilligeris instructum. Semina magna, compressa, discoidea, sæpe marginata, albida. Cotyledones foliaceæ, circa albumen curvatæ, plerumque incumbentes. Plantæ articulatæ ; articulis complanatis seu teretibus plus minus tuberculatis; foliis subulatis caducis axillâ pulvillos setosos plerumque aculeiferos gerentibus; aculeis apice retrorsum hispidis.

Subgen. 1. STENOPUNTIA, E. in B. C. R. Articuli complanati: flores parvi petala subulata: stigmata pauca.

1. O. STENOPETALA, E. 1. c.: prostrata; articulis magnis; aculeis 1-3 cum minoribus 1-3 ancipitibus deflexis atrofuscis; ovario pulvillis confertis stipato; sepalis petalisque subulatis suberectis; stylo inflato; stigmate simplici.

On the battle-field of Buena Vista, south of Saltillo. Nearly allied to the Mexican O. grandis, Hort. Angl., which has very similar flowers, but is an erect plant, with few and white spines, and 2 or 3 acute stigmata.

Subgen. 2. PLATOPUNTIA, E. 1. c.

Articuli complanati: flores

magni: bacca pulposa vel rarius sicca: semina late marginata: embryo plusquam circularis circa albumen parcum spiraliter convolutus : cotyledones semper contrariæ.

§ 1. Microcarpeæ: suberectæ : aculei plurimi, colorati: bacca parva subglobosa.

2. O. STRIGIL, E. in B. C. R.: suberecta, articulis ovatis orbiculatisve; pulvillis confertis; aculeis 5-8 radiantibus deflexis rufis apice flavis; bacca parva late umbilicata rubra; seminibus parvis anguste marginatis.

Between the Pecos and El Paso. — Plant 2 feet high; joints 4-5 inches long; spines an inch or less in length. Fruit 6-7 lines long. § 2. Grandes erectæ seu procumbentes: articuli magni: aculei pauci, validi, compressi, plerumque colorati: bacca major vel magna, plerumque ovata.

*Subinermes.

3. O. FICUS-INDICA, Mill: cultivated south of the Rio Grande, under the name Nopal Castillano.

** Flavispina.

† Erecta.

4. O. TUNA, Mill: cultivated about the old missions in the southern parts of Upper California, under the name Tuña. Specimens gathered at Beaufort, on the coast of South Carolina, (probably introduced,) may belong here.

5. O. ENGELMANNI, Salm: erecta, grandis; articulis obovatis ; pulvillis remotis setas stramineas rigidas inæquales aculeosque 1-3 compressos stramineos basi rufos gerentibus; floris flavi intus rubelli ovario subgloboso; stigmatibus 8-10; bacca obovata late umbilicata ; seminibus minoribus.

From the Canadian River to the mouth of the Rio Grande, and westward from the Gulf to Chihuahua and El Paso: fl. May and June. Plant 4-6 feet high; joints a foot long or less; late, 3-4 lines long; larger spines 1-1 - 3 inches in diameter. Fruit usually 2

leaves subu

inches long. Flower 24 inches long, 1 in diameter, Seeds 1 - 2 lines in diam

juicy, but of a somewhat nauseous taste. eter. A plant observed by Dr. Blackie on Bayou Bœuf, Western Louisiana, 5 feet high, joints 9 inches long, reddish-yellow flowers, is probably this species.