4i BRITISH HEPATIC^. 



II. GxMNOMiTEiUM, Oovda. 



Jung&i'Ttumnia, Lightf. Fl. Scot. ii. p. 786 (1777). Cesius, Gray & Bennett, Nat."" 

 Ar. Brit. PL I. p. 705 (1821). Schisma, Dum. Com. Bot. p. 114, p. p. (1823). Gym- 

 nomitrivm, Corda, in Opiz. Beitr. i. p. 651, n. 1, p. p. (1829); N. ab E. Naturg. der 

 Eur. Leberm. i. p. 98, n. 17 (1833). AcoUa, Dum. Syll. Jung. Eur. p. 76, n. xv. 

 (1831); Observ. Jung. p. 23 (1835). 



Dioicous. Colesule wanting. Involucre double, the inner shorter, 

 composed of two or more involute deeply-cleft and dentate leaves, 

 which enclose the short campanulate calyptra. Base of the young 

 fruit immersed in the hollow apex of the stem. Capsule globose, 

 4-valved, when empty reflexed. Elaters bi-spiral, caducous. 



Androecium distinct. Antheridia oval, stipitate, seated in the 

 axils of the perigonial leaves. 



Eronds fasciculate, ascending or erect, julaceous. Leaves di- 

 stichous, closely imbricated, emarginate-bidentate, glaucous-green, 

 creeping at the base ; flagellse radiculose ; examphigastriate. (2)e- 

 rivation — yo[Av6s, naked; jowrp/ov, a little cap.) 



Obs. — The name Ccesia was given by K. Be. Prodr. Fl. N. Holl, i. p. 277 (1810), 

 to a genus of Liliacece. 



Considerable diversity of opinion exists as to the import of the inner covering of 

 the fruit, — whether it should be considered an imperfect colesule, or an inner invol/ucve. 

 Typically, the colesule is supposed to be formed by the union of two or three modified 

 leaves ; but this is never really the case, since its development is always posterior to 

 the appearance of the pistUUdia, which it surrounds with a simple cellular ring. The 

 after-development varies in different species. I have hitherto been unable to find any 

 trace of the inner involucre in Gymnomitrium, except where pistillidia were already 

 present. The leaves are so deeply lobed, that it is difficult to make out the exact 

 structure (PI. I. t. 2, f. 6) ; but I think it is generally formed of three bracts ; two 

 anterior, and much broader than the third, whicK is posterior, and either simple or 

 bi-lobed (amphigastriate ?). They are usually connate at the base. In one specimen 

 I observed a smaller bract, interior to the rest, and inserted about halfway up the 

 calyptra, exactly as shown in fig. 7 of GoUsche's beautiful drawing of G. condnnatum 

 (Gott. <& Bab. Sep. Ewr. Ex. n. 423). Hooker's figures and description are inaccurate. 

 He describes the involucral leaves as " imbricated on all sides " (Br. Jung. t. iii, f. 3), 

 whereas their insertion is bifarious, like the ordinary ones. The innermost are said to 

 " form a cylindrical tube, scarcely distinguishable from a true calyx, except by the 

 longitudinal suture formed by the involuted margins : in colour and texture they 

 resemble the other leaves," and in figs. 6 and 7 they are represented with simple 

 inflexed margins, bluntly emarginate, and not at all toothed at the apex. Spruce 

 [Muse, et Hepat. Pyr. p. 127) first gives an accurate description of the parts. " In 

 some true Gymnomitria (e, g. G. concinnatum) I observe " (he writes) " within the 

 perichsetium two leaves (rarely only one) which are much shorter, wider, and more 

 tender than the perichsetial leaves, and unequally trifid with toothed segments ; but 

 these are neither connate with each other, nor concrete with the perichsetium ; hence 

 they cannot be called a perianth (col6sule), although obviously supplying the place 

 of one.'' 



