VOL. 5] Error in Genera and Species. 95 



fragment, kindly furnished me by Mr. J, G. Lemmon, shows it to 

 be a swollen form of the plant subsequently described as Allo- 

 caryastipitata.' Some misplacement of labels is to be suspected, 

 for the form is common in the Alameda marsh lands, particularly 

 about Mount Eden, and is sometimes even stouter than the one 

 in Mr. Lemmon' s herbarium. 



2. Although plants are bisexual, one or the other sex is apt to 

 preponderate in varying proportion. 



The influence of environment upon plants has been much con- 

 sidered, and seldom quite ignored, but the sexual differences, 

 unless they have progressed so far as complete separation, have 

 been little regarded. These differences are particularly notice- 

 able in incompletely dicecions annuals, and short-lived perennials, 

 where the greater sacrifice demanded of those which are practi- 

 cally female often appears to shorten the internodes, making the 

 plants lower and more stocky and the flowers smaller. Several 

 of the recent species of Sidalcea have no other foundation than 

 these sexual differences. The difference in development of the 

 flowers in different plants of Borraginaceae Polemoniaceae, etc. , 

 has most probably a similar origin. 



j. Hybrids, or rather crosses, are common among closely related 

 species, growing together. 



In Europe spontaneous hybrids are numerous and well known, 

 especially in Rubus, Epilobium, Hieracium, Cirsium, etc. In 

 this country they have been systematically studied only among 

 the willows. Our lists of species include, and perhaps unavoid- 

 ably, many of them, as they can only be certainly distinguished 

 in the field, and the collector seldom takes the trouble, even if 

 he suspects, to verify them. They rarely reach generic rank; I 

 believe, in our Flora, only one, Crockcria* which is most 

 probably a hybrid of Lasthenia and Eatonclla Congdoni, has been 

 made out with comparative certainty. Vauclevea 9 is, however, 

 a very suspectable plant. There is in the heads I have examined 



(7) Greene, Pitt, i, 19. 



(8) Greene, Bull. Cal. Acad, i, 03. 



(9) Greene, Pitt, iv, SO — but style tips, not "sub-terete." 



