1 66 DAVENPORT ACADEMY OF NATURAL SCIENCES. 



groups. The characters of entire, serrate, or glandular leaves, seems 

 to be more variable as a specific character, than is usually met with in 

 other genera, but occasional exceptions to uniformity in this respect 

 only emphasizes the importance of combining several characters in a 

 complete description, so that if one fails, the others may hold good. 



The leaf stipules furnish some well-marked characters; thus, while 

 usually thin and fugaceous in the Ea-ceanothus section, in the group 

 with annually deciduous leaves, they often persist till after the fall of 

 the leaf, as may be frequently seen in older branches of C. Amerkanus 

 and C. azureus. In the Cerastes section, they usually show a thick- 

 ened, corky, persistent base, often remaining as verrucose excresences, 

 while the slender tips are early deciduous. 



The inflorescence, while quite uniform in its general features, as com- 

 posed of an irregular series of umbellate clusters, offers good specific 

 characters in its more or less compact or prolonged thiysoid develop- 

 ment. The, separate flowers offer no important distinctive characters, 

 being remarkably uniform throughout, while the color, though usually 

 constant in the same species, is occasionally variable. 



The fruit offers some important distinctions in the shape and size of 

 the Cocci, the smooth, fleshy, or resinous exocarp, and the presence or 

 absence of crests or accessory appendages. 



GEOGRAPHICAL RANGE. 



The geographical distribution of the different species of this genus is 

 usually well-defined, and holds very obvious relations to the variations 

 of soil and climate. This is true not only of such as have the extended 

 range of C. Americanus, but also applies to such as are limited to a 

 comparatively small area. Wherever met with, they are inclined to be 

 gregarious, due, as I have above suggested, to the character of expul- 

 sive capsules, by which the seed is self-sown in its own locality. The 

 smooth, polished seeds, with their comparatively large cotyledons and 

 a liberal supply of albumen, seem thus calculated not only to maintain 

 their vitality under adverse conditions, but also to afford a vigorous 

 growth under favorable circumstances. It is, no doubt, owing to these 

 characters, that the Pacific coast of California constitutes the most 

 suitable home for this genus, and in its varied aspects of soil and 

 climate, invites to the largest display of specific forms. It thus hap- 

 pens that there is no considerable expanse of country in this region, 

 especially on the foot-hills or the mountain slopes, that is without its 

 exhibit of one or more of these characteristic shrubs. If asked to 

 designate a spot where they occur in the greatest profusion and variety, 



