CONTENTS. 
Page 
OTE COIES, «Gt 0 SN cc rr A eae ee eee I~4 
DEEP eASOOCIATIONS AND HABITATS, .-...'..-.03 0-4 o0sees0ss0 03s we 5-2 
(1) The river and irrigating ditches; association of hygrophytes........ : 
(2) The river banks; association of cottonwoods and willows........... 8 
(3) The flood-plain; mesquite forest association...................0.. 9 
(4) Salt spots; association of salt-bushes...................... ae 13 
(5) The wash; palo verde-catclaw association. ...............000.005. 14 
(lee eMNeSisIKG SlOPeS 25.5...) 2 ans +s euers Ee Oe Ee ee. 16 
(Ce reocote- bush associa tion, £5.08 ot a. oe ee ee 16 
(Gye raticeria association sagcctek « tlre edge pees eee, eee gee 17 
Mie LGN A sah cas. ial, tease, ot icant its eit pee. EET. tick Pam? eae SE ae 18 
(a) Association of Fouguieria and Parkinsonia microphylla....... 18 
(b) Association of Cereus giganteus and Encelia farinosa......... 18 
KC wi Opi ASSOCIA i@tbin chute r Sale a ee ant ene ti ee 19 
(GeV PUN IONANG ASSOCIATION wate ch tee atte his lease 19 
(5) ‘Superficial soil dayerss association of annuals 5 «21040 0 a ass 20 
(a)\eonade-loving cpectessiy. oo. nik. Aiea. Sieg ees A Bas, Beet ad 20 
COL Isnt lovin ne sertes ey a A det ka iy ne ce eee es 21 
(Oe aia ctlic ati svt DINE PEAILS snes 9. ora dubctite «pd cot eite Aes ae 22 
Pichens or the Desert :Labottory domatt, 046 wwe hie ass dabeyan 24 
Oe Miscella nents initoduced SNCCIES., 7 cos couse eke ee as uNdee 27 
LIMA COCAL MI MSTRIBUTIONIONROPRCINST, Anmiew a¥ ea ds 5 SHEE. fh od. es 29-66 
Hops piic na isoll relations, fe 2 ee eos dee. Pel 29 
ORCL UPENOSU LED, Set PREP tyr ee ates ee A OE RE, 29 
aE TALE HLG Ma ee Be ae dinss AM Che thin 38 tei Aaa Bea dyin @ 3PM t 30 
FEU POCA TILTED IMac xi hon Re Mes OMe yh te Rew teen 8 2 eo ed Gate 31 
PCL OTIC PAIN rhe es... AE a Oe meee sc ee EP Ba 
EA OLD TO DOU Aine x OM Bat Sie eee Nant aera aie Suny’ Sylpeive ep ayers hs 36 
COMPARA Ca SUUCIOS Terai s PIT oe wise jetn ou, eine Dee wales baa Te a 
NEedS a idles PENCIES Ol GISDEL S31. We aes 2) ee Peg el. Ge OI es 47 
Tea 10 ie COM Perition aN SUCCESSION: fy occ pee. oe bao sin osha 2 51 
Habussnd stticturesirelatedto, distribution. f.-0: 6.03 Bi a Ly 
a he. root-systemol Cereus c1vanteus, 6443 6 ese fda ed ae vss 59 
TAD ENVIRONMENTAL AND? HISTORICAL, FACTORS)... 0. foe ee eee cee ene 67-102 
The geology of the vicinity of the Tumamoe Hills............5......... 67 
eta (abl yam en et eh te a dda ped y atek.k 73 
Cy er eR tt ee ree tN aN No Sines wip. ee v2 Sy she 74 
tee i ern re ee oie a oan ss Sie Sip TE Ge aye 79 
Piletemlstomtesescrt | abOratory COmainy vec 8 bak feel ns ne es be ess 83 
ETE OS COW ATA EN TRTTES fo) oe Boe PM lt a Oe As iad a a a 94 
(ISSR ES ONSEN lho © Dec Renata ia aie! ok! a nr 94 
Pemipers etre tecorde ea ianen ee cu avs et 5 Fhe steko avoss 96 
DiCastitemenia OmevanGla MOU RE Raa Pee re eo kk Saw elk 99 
PITIAES Ol 1 ett Ota OLY COLA ie ees in Se ee a 101 
IV. VEGETATION GROUPS OF THE DESERT LABORATORY DOMAIN.......... 103-112 
Ve. LH ORIGINGORS DESERT CHLORAS ace aia al tts Aes kee hep aes 2 113-119 
Rote uy Wd NIE LITSCUSSION tac 4 ee ene, In nae 9.2 8d wiring lee I 21-137 
‘Lhe plantassociat ions, 24r Greree eam fulton 1. telat es Wa SS. 121 
Heaphiorelationsy. 2005.21, 22S Pee CAO IG Are aC sy. B22 
Concurrent action! different factors oq. 0 es cee as, Phen | 127 
OCA UMD Y CINETILS oo ha <tae ieaen e Tie oens  e 9S: oo COD va" 
General movementss.ic0 SOe es ee Oe Gere et eta., Plas 134 
RRR UMERERE Vere ee et is fee oe ee a ee it OM eet ye nae batt ai 139-142 
SEES SI 9 La 3 cn ele ae Ke Par eee Soy ie eae nn ae 143-144 
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