821 



ON HOLOSCHCENUS Link. 

 By C. B. Claeke, F.R.S. 



E. Brown (Prod. 1810, pp. 221, 222) split the genus Scirpus as 

 it then stood into two, on a single differential character, viz., 

 Scirpus, " Setse hypogynae obviae " ; Isolepis, " Setae nulla*." It has 

 been found, since 1810, that in numerous species of R. Brown's 

 ScirjMs the hypogynous bristles are not rarely very small, reduced 

 or subobsolete ; very rarely are they so completely absent that no 

 indication of them can be microscopically detected ; they are 

 (probably) rudimentary petals and stamens, in the (geologic) course 

 of disappearance, and some traces of them perhaps could in most 

 instances be discovered by a study of the development of the 

 flower. They are, however, frequently so nearly obsolete that their 

 value for practical separation of genera is far from absolute ; hence 

 both Boeckeler and Bentham have reduced Isolepis R. Br. back to 

 Scirpus, and nearly all modern authors have accepted this reduction. 



Nevertheless, R. Brown was not far wrong. The absence of the 

 hypogynous setae in Isolepis appears to be absolute, nor do I ever 

 find (accidentally) any trace of them present. The two large 

 " squamas iaterales V noted by Bentham (Benth. et Hook. Gen. PI. 

 hi. p. 1051) as found in one single collection of Scirpas mem- 

 branacens Thunb. (Isolepis Nees) are so very unlike the ordinary 

 setas hypogynae of Cyperacea that they are not supposed by Bentham 

 to be homologous with setae hypogynas. Indeed, the ultimate result 

 is that, for the subdivision into genera of the great mass of species 

 now called Scirpus, any better subgenus than Isolepis, and any 

 better character than R. Brown's, still remain to be discovered. 



As a split off from the then-accepted genus Isolepis, Link (Hort. 

 Berol. i. (1827), p. 293) founded the genus Holoschcenus; in its 

 short character he stated, " Setae hypogynas nullae " ; and he 

 appended to the character the remark, " Genus inflorescentia 

 distinctum." To this genus would belong Scirpus Holoschcenus and 

 S. JRomanus Linn. Sp. PI. 72, S. globiferus Linn, f. Suppl.j*. 104, 

 and Isolepis Thunberyii Schrad. in Goett. Anz. 1821, heft 3, p. 2068. 

 Though the genus would appear from Link's words to be a weak 

 one, and though it has been sunk into Isolepis (and finally into 

 Scirpus) by modern authors, it was accepted and specially investi- 

 gated by the elder Reichenbach. He (in his FL Germ. Excurs. 

 i. (1830), p. 75, and in Flora, xiii. (1830), band 2, pp. 489-501 

 and 517-521) discussed the genus, added new species, and con- 

 cludes, Flora (1830), p. 519, "Die Gattung Holoschcenus (Dalech.) 

 Lk. ist uebrigens eine der allernatuerlichsten unter den Scirpinen," 

 &c. He states also that he studied several of the %i species" alive 

 in his botanic garden. Reichenbach in these labours was mainly 

 employed in species-making, on characters of very secondary value, 

 and he says nothing about the setae ; in his FL Excurs. he places 

 Holoschcenus among the genera "calyee nullo," i.e., it had no setae. 

 Leaving out of our present consideration the Cape plant (which 

 differs a little, and is accorded specific rank by Boeckeler), Reiehen- 



Jouknal of Botany. — Vol. 30. [Nov. 1892.] y 



