724 MINNESOTA BOTANICAL STUDIES. 



lected by Wosnessenski in the vicinity of " Ross" (that is, near 

 San Francisco) on the coast of California in July, 1840. The 

 material communicated to Ruprecht comprised some middle- 

 sized plants and some younger specimens, but did not, appar- 

 ently, enable him to see either the sporelings and unilaminate 

 stage or the mature, full-grown form. Consequently his meas- 

 urements need modification and the specific description should 

 be revised to include much larger plants. Anderson is the only 

 one who has written on the plant in whose account a knowledge 

 of full-sized plants is indicated. In his Natural History of 

 Santa Cruz county * it is stated that the stem is from one to six 

 feet in length and that the leaves are from one to five feet 

 long, " all without a midrib except the central one into which 

 the flattened stem seems to be lost, giving it the look of a mid- 

 rib." 



It was from Anderson that Areschoug received his specimens 

 of PterygopJwra upon which, together with those of Ruprecht 

 sent him from the collections of the Academy at St. Petersburg, 

 he based his brief study as set forth in Observationes Phycolo- 

 gicae.f In this paper Areschoug gives in compact form the 

 generic and specific description and adds some observations and 

 corrections to the earlier account of the Russian botanist. 

 Areschoug observes that the number and nature of the growth- 

 rings in the trunk seem difficult to define. He is skeptical con- 

 cerning the lacunas muciferse, although he retains in his revised 

 description of the genus the phrase " ad peripheriam internam 

 annuli intimi collocata, interdum biseriata," crediting the ob- 

 servation to Ruprecht. He reexamined the younger specimens 

 upon which Ruprecht's original account was based and gives a 

 condensed description of them. The youngest plant seen ap- 

 pears to have had a stipe 20 cm. long and 2-5 mm. broad with 

 a lamina 35 cm. long and 6-7 cm. broad. As will be seen later 

 my own plant, " B ", indicates that these measurements, based 

 upon dried material, need correction. Areschoug received mate- 

 rial from " Vera Cruz," California (meaning Santa Cruz), sent 

 him by Dr. Anderson and notes, doubtless upon the authority of 

 Anderson, that the plant grows also at San Francisco. In 



* Anderson, C. I/. The natural history of Santa Cruz county, Oakland, Cal., 

 24. No date. (1892?) 



t Areschoug, J. E Observationes Phycologicae, Part 5: De Latninariaceis 

 Nonnullis, n. 1884. 



