43 CONTRIBUTIONS TO WESTERN BOTANY NO. 15 



purple-flowered rather than white, Why? presumably to strengthen hh 

 reference of certain Thelypodia here. I have never yet seen a ycUow 

 fiowered species except in Stanleya. All the rest are greenish yellow if 

 at all so. Practically all the species of Thelypodium, Caulanthus, on-l 

 Streptanthus have petals fringed with purple the body being greenish 

 and whitish, this includes Streptanthus longiro^tris w^hich is a gor/d 

 Streptanthus, where Watson placed it at last, and apparently is congeneric 

 with T. Cooperi and deserti. His reference of Thelypodia 'to Sisymbrium 

 IS niade under excessive strain, and he still more disrupts that '(^enW.-^ to 

 do It It is not a question of the existence of taxonomic diffiru^i -s. 

 These we all admit, but the question is on the expediency of treating 



tliem. 



knot 



genera but this do^s not at all solve the question of rciationship. Tt 

 Js still tliere. It is a short cut to avoid explaining the genetic tangle, 

 and It is_ not scientific, but it catches the eye of the ignoramus, who at 

 once begins to toot the wonderful insight and discoveries of Rydbe-^', 

 when m fact he is only repeating what we older botanists sav/ and pub- 

 isshcd when he was in knee pants. 



Taking up Sisymbrium as Payson treats it we find it sometimes 

 hangs on white or yellow flowers and always on a stignm lobed at'rieht 

 angles to the valves. What he would do with thos^ species of Th^Iv- 

 S"l ^^ "f^^^.f \noJcbed stigmas he answers by assuming' that th^v 

 would be lobed if they had a chance, and ^v-ould go where he^has placd 



htf of T?li f ' ""V' ''^' ^' ^^'° '^^^ that the septum is never 

 m. Lii ^'^ ''"'• ^^* ^^ examination of my T. elegans shows tl^ ■ 



TIevnndfnnr?^^'"^'''\''^''\''^ '" ""'^'^ '^''''' ^^^^^ ^^ stains in 

 Iheljpodium this i'3 where the septum is narrow, then the celJr, are con- 

 tracted and elongated This distinction shades to nothing in IsTo^k^ 



Se on?/ -ir" 'f '^ '^ ^^ '^- '^'^^- '' '^ difficult Ltl^i.: 

 r o'!;.,n?t T 7 Sisjonbnum to admit such clear species of Thelv- 

 fo nn tTn ^' ff""' ""^1 ^'^bi.guum into it. There seems some reason 



inc lic.r-leaved Ihelypodia of the Arizona region, there for thev a-e 

 r;S:L-nto7 the " ;^^^"^>?^f-\ ^^^ the^poi ha.:; [he tine: 

 "nVin rZld no nl 'ti^ ?' l"^^''"' i"^° ''^' ^^' ^^ S. altissimum. I 

 nlon.^ with m! T ^ S^T ^^^■'>T^?^"^ Cooperi in Caulanthus ar, it 

 r oslis ^^i^/ I thin? h J'""' K° ^'- "^r ^^"Seneric with Arabi. longi- 

 th°ri~ is still ?nt^ if? ^'-1 '" S^^^Pt^^t'^us- The thickening of 



is no reason why o'hers should do wone iTT^ ' '''''' °f ''" ^^ 

 been for a long 'time a tendercv to di^tdit v'7 ' '^''''T'l '''''' ^''' 

 n^ore ecological horse sense anJ iJo^'^Se:;^:;^^.::;^^ ^^ ^^^ 



