BOT.— Vol. II.] NOTT—CALIFORNIAN NITOPHYLLA. 9 



Offshoots and Iniiovations. — A point of further interest in 

 connection with the development of the prostrate frond is 

 found in the formation of offshoots and innovations. In the 

 first case, slender branches may arise from the margin of 

 the older portion of the frond. These grow, secure attach- 

 ment for themselves, and separate from the parent frond, 

 and later give rise in turn to erect fronds. In the second 

 case, by the growth and branching of the prostrate frond, 

 an extended structure is produced, the ramifications of 

 which become separated from each other by the decay and 

 disappearance of the older portions, thus forming innova- 

 tions in a manner similar to the process occurring in the 

 Bryophytes. 



The Erect Frond. — The erect part of the plant commonly 

 rises singly from the prostrate portion, but occasionally the 

 fronds are clustered together, as in N. multilobum, where 

 they are grouped in the middle of the orbicular patch 

 formed by the prostrate frond. 



Size. — The height and breadth of the erect frond is an 

 extremely variable character, IV. corallinarum, occurring 

 upon Corallina chdensis, does not reach a height of 2 cm. ; 

 while N. s^ectahile is reported by D. C. Eaton as reaching 

 50-60 cm. 



Shape and Branching. — Great diversity exists in the 

 shape and branching of the erect frond. Some species are 

 broadly membranous, and but slightly lobed or divided. 

 Good examples of this type are JV. spectabile, N. Iatissimu7n 

 and JV. fryeanum. At the other extreme may be placed 

 such a finely dissected and abundantly branched species as 

 N. andersonianum . Between these two opposing types are 

 found all gradations of frond division and arrangement of 

 branches. It is not uncommon to find in one and the same 

 species forms exhibiting a tendency to become broadly 

 membranous, or very much divided and branched. For 

 instance, in N. rtiprechtianuni, there seems to be a ten- 

 dency toward the flabellate or expanded type of frond, 

 though the typical specimens of the species are character- 

 ized by division of the frond into linear, much prolonged 



