578 CACTACEAE 



areolae on the ribs or the tubercles. Flowers arising close above the spine-bear- 

 ing fully developed areolae, hence appearing lateral on the stem/ Hypanthiuin 

 prolonged beyond the ovary, scaly. Style filiform. Fruit fleshy. Seeds tubercled, 

 endosperm scanty; embryo straight. 



rnpoll^ f H^^^^' ""'^^ °t the stem about 13. 1. E. viridiflorus. 



Corolla red or purple; nbs usuaUy less than 13. 

 Ribs of the stem 8-12. 



Flowers scarlet; central spmes 2-7. 



Central spines aU terete; flowers 4-6 cm. long, yellomsh inside. 



T ^^ 4. 1 • , 2. E. aqgregatus. 



iri^«^ central spine quadrangular; flowers 8-10 cm. long. 3. E, Roemeri. 



i*lo\\ers purple or violet. 



Central spines 4-5, straight. 4. E. Engelmannu 



Central spmes sohtary, bulbous at the base. 



Central spme terete; radials 12-25 mm. long, the lower stouter. 



^„ . , . , 5. E. Fendlen. 



central spine angular; radials 2-5 cm. long, the lateral ones strongest. 



Ribs of the stem 5-7. ^- ^- ^^iavensis. 



^^^i^tlJ^^^® present. 8 cm. long, angled and grooved; radials 6-8, strongly 

 Central spine wanting ; radials 3-59. almost terete. 8." E. paucispinus. ' 



9 fJ; ^' ^^$^?°^y^^ Engelm. Stem globose or sometimes oblong-cyHndric, 

 fo iV '^^- , ^^' ™^. ^^' ^^^^'^' central spines solitary, stout, straight or curved, 

 ;;h ^-"l"- % I^"«gated with purple and white; radial spines 12-18, strict 

 and radiatmg, 2-6 mm. long; flowers 2.5 cm. wide, greenish brow without, 



W^n w f r"" ^^^'''a ^r^'*^ *^^P*^°' 1^12 mm. long. Plains and hills: Tex.- 

 vvyo. — JN.M. i^on. — Submont. 



r-rr.^'!.;^; agi^egatus (Engelm.) Rydb. Ovate or subglobose, obtuse, 3.5-7.5 

 «^;rii '/ cin._ thick, cespitose in hemispheric tufts; ribs 8-11, tubercled; 

 E?pr .P.?' ft^^-iglit, terete; radials 8-12, white, 6-12 mm. long the upper 

 W 9'^??''^ spmes 1-3 stouter, 1-2 cm. long; flowers deep scarlet, 3.5-6 cm 



«nrf nl«t"=:^°'' n^' ^^""^"^ coccineus and C. phoenicem Engelm. Hillsides 

 and plams. Tex.-Colo.-Ariz.; n Mex. Son. Submont 



inJv bA^.?!^^''-l^^'^^''Pu^-^ Engelm. Stem ovoid, 7.5-10 cm. high, spar- 

 wSh hnZf k' "^' Jrll, obtuse, tubercled; spines whitish or straw-colored, 



ratera^l2 In ^t^l' "'"^'''^ ?~]^' '^^''^^'' '^'^'S^t, the upper 4-10 mm. long, the 

 duskv wW ^ lo"g; central spmes 3-5, very bulbose, the lowest quadrangular, 



cm IZ fZ^ ^^' u^^/ '^- ^°^g' Por'-ect or reflexed; flowers scarlet, 8-10 



Pln'in«^ ivr M n"l" ^''??1-r ^^^^^^ RoemeH Muhlenph. C. conimdes Engehn. 

 riams. JN.M.— Colo.— Cahf.; n Mex. Son. 



^7tr^\h!^F^^^^ ^^^"^^ ^^™- Stem elliptic-cylindric, 12-30 cm. high, 

 Sinl ;nW« 'iH?^%*""^P^""^^>^ branched; ribs 10-12, rarely 13, tubercalate; 



It^o^ W f^ ?'^^'" ^to^t^st; central spines 4 (or 5), straight and angled, 

 flower ^dv^'^T*" ""^1^^" ^^f""^'' straight, the lowest white, porrect or reflexed; 

 D^rtf^^lTah-cSi^E^Calf ^^^^ ^^^^^ ^..eZ,na..^ Parry. 



cm \Sh ^^??!S CEngehn.) Rumpl. Stem ovoid or ovoid-cyhndric, 7.5-20 

 5^10 straight nr.n;,%*^lt'"?*^''' ^espitose; ribs 9-12, tuberculatc; radial spines 

 Sntr^ s£ 1 ,to^,?^' ??.^r^^* ^to"*est, white and angular, 12-25 mm. long; 

 2^5lm^?oni- flnul^^ w ^^'''^ ^* ^^^ base, curved upwards, reddish black 

 c^ W' DurnTe ^.tn ^^^l^^P'''?,^"' ^^-^ ''™- ^road; fruit ovate-globose, 2.5-S 

 mah-&i?.Tn M^x'/c^^^'- ^^"^ ^^^'^^^ ^ng^hB. Dry plains: Tex. 



cm^hiS SSiellTffJ^/^"^--^'^"^^^-) ^^P^- Stem ovate, glaucous, ^8 

 c^tSl sDine aL^r ;,f%°''''^ "^^^^ ^ ""■ ^ide;ribs 8-12, slightly tubercled; 

 st?urn,?wd ^nft' f"^^^i ^^f^^^ upwards, 3.5^ cm. loni; radials 5-8, 

 2TcmVn^\lfu?^l'}'''^''\ f"'^^ ?^ ^'ith tWny tips, the upper and lower 



f r4 obloni' 2 i-l .1 1 ''°'' ^t^^ "^- ^^^^^ Sowers deep crimson, 5-7 cm, long; 

 iruit oblong, 2.^3 cm. long. Deserts: Cahf .-Utah-Ariz . Son. 



