STIGMATA. 



[ 617 1 



STILBUM. 



cavity of the ovary. It is situated either at 

 the summit of the style or its branches, or, 

 when this is absent, it is sessile on the ovary. 

 The surface of the stigma is clothed \Adth 

 papilliform or short tubular cells, from which 

 a saccharine secretion exudes at the period 

 when the ovules are prepared to receive the 

 influence of the pollen-grains. In this fluid 

 the pollen-grains produce their tubes, which 

 make their way between the papillae to 

 descend through the conducting tissue of 

 the style to the placenta (PI. 32. fig. 30). 

 These papilliform cells in a young state often 

 form favourable subjects for the study of the 

 protoplasmic cell-contents, and also of the 

 fluid colouring matter. The forms of the 

 stigma are exceedingly varied and sometimes 

 very elegant. In the family of Composite, 

 its characters are used for the systematic 

 division of the numerous genera. 



STIGMATA, OF Animals. See Spira- 



CLES 



STIGMATEA, Fr. See Dothidea. 



STIGONEMA, Ag.— A supposed genus 

 of Scytonemeous Oscillatoriacese (Confer- 

 void Algse), founded upon what has proved 

 to be the thallus of a genus of Lichens. See 



STILBACEL— A family of Hyphomyce- 

 tous Fungi, growing upon decaying animal 

 or vegetable matter, or on bark or leathery 

 leaves. Characterized by a wart-shaped 

 receptacle, composed of conjoinedfilamentous 

 or hexagonal cells and spores borne singly 

 on the apices of free filaments. Some of the 

 Fungi here included are heterogeneous and 

 imperfectly studied, for example, Tubercu- 

 laria and Fusarium are apparently only im- 

 perfect states of other Fungi, while the more 

 distinct genera appear to be referable to the 

 family Dematiei. 



Synopsis of British Genera. 



I. Stilbum. Receptacle stalked at the 

 base, clavate or capitate at the summit, com- 

 posed of coalescent, densely crowded, parallel 

 filaments; spores simple, arising singly at 

 the apices of free filaments. 



II. Pachnocybe. Receptacle stipitate, 

 clavate, floccose, the filaments twisted, the 

 head finally pruinose, with simple spores. 



III. Periconia. Receptacle stalked at 

 the base, clavate or capitate at the apex, 

 composed of coalescent, densely crowded 

 parallel filaments, or cellularly fleshy; spores 

 simple, crowded on simple sporophores ari- 

 sing at the summit (and on the stalk. Fries). 



IV. TuBERCULARiA. Rcceptacle wart- 



shaped, globular or stalked, fleshy, composed 

 of continuous, sterile and thread-like, beaded, 

 fertile filaments. Finally indurated, floccose, 

 with the spores scattered over it, or falling 

 into powder. 



V. Periola. Receptacle cellular, ses- 

 sile ; fertile filaments abbreviated, torulose, 

 mixed with septate, lax, sterile filaments. 



VI. VoLUTELLA. Reccptaclc wart-like, 

 cellular, compact, with long rigid bristles ; 

 spores spindle-shaped, septate, on continu- 

 ous short filaments, arising all over the 

 receptacle. 



VII. Fusarium. Receptacle wart-like, 

 cellular, gelatinous ; spores spindle-shaped, 

 simple, somewhat curved, borne on simple 

 filaments arising all over the receptacle, and 

 forming a discoid stratum. 



VIII. Illosporium. Receptacle wart- 

 shaped, subgelatinous, diffluent ; spores 

 simple, pellucid, generally with a hyaline 

 envelope, borne on short filaments. 



IX. Epicoccum. Receptacle wart-shaped, 

 cellular, for the most part seated on an 

 efi^used patch; spores four-sided, cellular, 

 attached singly to very short, continuous 

 filaments. 



STILBOSPORA, 

 Pers. — A supposed 

 genus of Melanconiei 

 (Coniomycetous Fun- 

 gi), but apparently only 

 consisting of stylospo- 

 rous fruits of SjjhcericB. 

 These grow upon wood, 



sticks, &C., breaking StUbospora macrosperma. 

 forth on the surface Group of conceptacles 



without any distinct breaking forth on a frag. 

 .., . *' .J. ment or wood; nat size. 



perithecuim, COnsiStmg The detached spores on 

 of a nucleus composed t^^e right-hand magnified 

 of agglutinated (sep- ^^O diameters. 



tate) stylospores (see Sph^ria). 



BiBL. Berk. Brit. FlorA\.pt.2.^. 356, Ann. 

 Nat. Hist. vi. 355, Hooker's London Journ. 

 of Bot. iii. p. 322; Fries, Summa Veg. p. 

 508 ; Fresenius, Beitr. z. Myc. heftii. p. 63. 



STILBUM, Tode.— A genus of Stilbacei 

 (Hyphomycetous Fungi), containing a con- 

 siderable number of species, forming little 

 shining mildews, sometimes brightly co- 

 loured, on decaying wood, herbaceous plants. 

 Fungi, &c. The stalk-like stroma differs in 

 character, being sometimes villous, some- 

 times glabrous and rigid, sometimes pellucid 

 and soft ; it is formed of conjoined filaments, 

 the free ends of which bear the spores in a 

 capitulum, which finally exhibits a gelati- 

 nous character. 



