lS6i COKTRIBUnONS to WESTEKN BOTANY NO. I* 



r 



Hermosillo in 1926. Petals 3-4, almost rotate-mreading, concave 



clawedi 1 am l<mg, the upper two-a little stnaUer, contiguous; the lower 

 pair q>posite and occnpying &e middle^ there being a distinct hiatus 

 irficre the fiWi petal ishould be, and ^15 space occupied by the declined 

 stipe. Th» gives^ the appearance o£ a^ leguminous flower with the keel 

 absent Stamens widely spreading, and with filaments arched. Anthers 

 acute, linear, extrorse and curling inward when open. Stipe of pod 1 cm, 

 long, very slender, as is the not capitate style. Pods arraa^ as are the 

 testicles of d<^. To my mind the attempt to break this geanus up into 

 several species is futile because the characters have no ecological or struc- 

 tural worth. In the north, where the colds of winter make real differences 

 in ^cture dfesirable and useful to the plants, certain characters have 

 significance, but in the south, where there is no cold to combat, we cannot 

 rany our methods and make them apply to ccmditions of growth, which 

 are the only determining factors. There are many plant structures which 

 in their native areas have significance, and those plants having them take 



them a3 thty migrate to other life ones, and which in time they drop 



fit 



as useless organs, but wBicE at the present time are not entirely 

 ated. For example, most of the pears and cherries are immigrants from 

 the south and have evergreen leaves which they are hard to lose. The 

 same is the case with the Sycamore (Platanua racemosa), which also is a 

 fTue ex'^rgreen, but in northern Mexico and California tries to become 

 dedduou*. The reverse is the case with the elm, which is a nautral 

 iduous, bat which carrier this tendency everywhere to shed its leave* 



in th^ early faH in the Trc^ics. The same tendency,, tltat of holding over 



the wmter, is seen in the Eschscholtaia, in Helianthus annuus, in most 

 winter annuals, in WisHzenia, in Gossypium Barbadense, which in Cali- 

 fornia- 13 an annual but in most of Mexico is a woody shrub, etc. 



lodanthus striatus N. Sp. Erect annuals, 2-3 feet high, copiously 

 IV" l/^fi"^ y i'^^*^^* throughout with ascending branches. Whole 



ft-ith short 



anceo- 



■jni smeoth or the older ^id Ibwer leaves sometimes pubescent 

 ^4 snnple hairs. Leaves thin, 2-3 inches long, ovate-acuminate 



icuminate with cuneate base and slender petiole about half a? long as 



blade, mostly entire, but lower ones sometimes, sparselv dentate. 



rio^ m long and terminal, racemes which are bractless, white. Sepals 



alKXit .? mm. long, narrowly elliptical, green, with white margins, several 



erveft, tiiirr, the cuter ones rather saccate below. Petals oblanceolate and 



rouafted. w^ith two pairs of short teeth on the sfdes, distinctly clawed, 

 .^areacJing, 6-7 mm Iwig, conspicuously nerved. Stamens ovate and acute. 

 yods about an indk Irag, mostly horizontal, flattened parallel with the 

 partition, smooth, a little torulose, conspicuously several -nerved, shortly 

 HTipitatc, eonspicuously beaked with beak fully 1 mm. long. Stigmfl-. 

 rarely a Ii^e Tobed transversely. Seed* <*ltog, not winged, yellowish, 

 about 12. Partition very thin, with short and rather oblong but distorted 

 .^leahe.. Pedicels filiform, about 6. mm. long, spreading. This plant has 

 the technical characters of Idodanthus more than of Dryopetalon but it 

 h^ the toothed petals of the latter, and grows in similar situations. 

 vVa-te places, Todos, Santos^, February 17, 192». in washes north of th« 



