MAMMILLARIA 



BB. Spines one or more hooked and 



central, except in M. pttsilla 



and M. dioica insularis. 



c. Bristles one or more found 



in the axils between the 



tubercles 40. 



41. 

 42 



MAMiMILI-ARIA 



973 



Wildii 

 tetrancista 

 dioica 

 armillata 



cc. Bristles none in the axils, 

 except perhaps in M. Car- 

 retii i 



\A. Juice Milkif voiie in the tubercles, 

 but found or to be suspected in 

 the body. No hooked spines. 

 Radial spines less than 15; 

 centrals usually 1. 



B. Fls. yellow 52. 



BB. Fls. blood-red 53. 



BBB. Fls. carmine 54. 



55. 

 5f.. 



Tuiee milky exuding from 

 wounds in any part of the 

 plant: stems not elongated: 

 tubercles usually angular: no 



Wrightii 



Goodrichii 



Grahami 



venusta 



Mainae 



Carretii 



deflexit>pina 65 

 densa 30 

 denudata 34 



discolor 57 

 dohchocentri 

 echmana .id 

 echmata SO 

 Echinus 9 



Heeseana 67 radios i _o 



hemisphserica, 70 Eadhana lb 

 Heyderi 70 raphidacautUa 



Wright 



1. raphidacAntha, Lem. Stems becoming 1 ft. oi more 

 long, 2-3 in. in diam., often clavate: tubercles erect- 

 spreading, somewbat flattened, often with 1 or 2 glands 

 in the groove: spines yellow in the young state, soon 

 gray; radials6-10; central 1, longer and stouter, straight 

 or hoolied in the same plant : fls. about 1 in. broad. 

 San Luis Potosi, Mex. — The more constantly hooked 

 form is M. ancistracantha, Lem. 



2. macrothMe, Mart. (M. aulacolheje. Lem. M. Lih- 

 manni. Ottoi. Stems .-itout, attaining nearly 2 ft. in. 

 lieiglit by 4 in. in rliaiii. : tulifrcles long, conical, at first 

 upright, in age beconjiiig even deflexed: spines all yel- 

 low: radials li-8, spreading; centrals 1-2, longer and 

 stouter: fls. \Y!.-1 in. broad. Central Mex. 



3. er^cta, Lem. Branching from base and from de- 

 cumbent stems, attaining 12 in. or more in height by 3 

 in. in diam., bright green: tubercles conical, short, up- 

 right: spines all yellow; radials 8-13 ; centrals 4 or 

 less: fls. 2-2K in. in diam. Cent. Mex.— In the groove 

 close to the spines is often found, especially in the 

 flowering area, a conspicuous honey gland. 



4. recurvata, Engelm. (M. ni-nn-inpiiiii . Kii-elm. 

 U. NogaXensis, Runge). Stems ,|..i.iv.-,.,I^Im1„,-,. ■m^i 

 often deeply concave, 6-8 in. in (li;iin., iMitiinm Lul'i' 

 masses 1-3 ft. in diam.: tubercles n1i..ii. wiili usually .i 

 large gland in the groove near the ain \: -pine^ yellow 

 or whitish, stiff, recurved-peetiiiaie, int. iwoveu and 

 covering the whole plant;' radials Is-L'n ; eenti-al 1, 

 rarely 2, recurved: fls, about 1 in. h.ni,-. Inowiiish out- 

 side. Near Nogales, Arizona, ami southward in Sonora. 



5. Scheerii, Miihlpf. Sinns ,,v it.- .'loliose, 3-6 in. in 

 diam., usually simple: tnlinel.- Iai-:;e and distant, 

 deeply grooved, with l-.'i ^lan.ls in the groove: spines 

 stout, rigid, sometimes re.Mi-li; radiiils'6-16; centrals 

 1-5, stouter and longer, 1 very stout and porrect : fls. 

 2 in. long: seeds large for the genus. S. W. Texas and 

 southward in Mexico. 



6. robustispina, Encelm. {M. Br/iwnii. Toumey), 

 Much like the ina.ee.lin-. I.ut tnl.en-les t.-n-tish, no 

 glands in tin- -n.,,ve ..,■ .,,nnlM>a- a Mii-ir .a,e at apex: 

 spines very stout; ]-a.lia|s in-i:, ; .-entral 1, longer, 

 Straight, curved (.r ev.n hooke.l. rareiv an additional 

 straight upper one: fls. 2 in. long, with very slender 

 tube: seeds large, Babuquibari mountains south of 

 Tucson, Ariz, 



