STICTINA. 



[ 738 ] 



STILBACEI. 



brandies of trees, &c., bursting througli 

 from beneath the bark when matiu'e. Stidis 

 (Cn/ptomt/ces,Ikv\i. ; Propolis, Fr., ^S". Vcff.) 

 versicolor (figs. 697-600) is common on 

 wood ; the upper surface of the open fruit 

 is white, and at length mealy. 



BiBL. Berk. Br. Fl. ii. pt. 2. 214 ; Ann. 

 N. H. vi. ooO; Fries, Sum. Veg. 372. 



STICTINA, Nyl.— A genus of Phyllodei 

 (Lichenaceous Lichens). Thallus variously 

 lobed or laciniato-lobate ; rhizina3 simple ; 

 granula gonima of a dark blue-green colour. 

 (Leiohton, Z«r7/(.i^/. IDS.) 



StiCTODIS'CUS, Grev.— A genus of 

 Diatomacese. S. Hardmanianus, in the 

 JNIonterey deposit. (Grev. Mic. Tr, 1865, 

 98.) 



STIGEOCLO'NIUM, Klitz.— A genus of 

 Confervoid Algfe, doubtfully referred to 

 Confervacefe, growing mostly in brooks, 

 and composed of delicate branched fila- 

 ments, drawn out into delicate hyaline 

 points ; attached to stones aud forming 

 masses of a mucous or lubricous character. 

 The jointed filaments are composed of short 

 cells, possessing bright green contents ; the 

 entire contents of a cell are converted into 

 a single spore (with four cilia) and dis- 

 charged (PI. 0. fig. 5) ; and the cell-wall is 

 so delicate that it generally vanishes at the 

 same time. Many species are described by 

 Kiitzing, formerly regarded as members of 

 the genus Dkapaenaldia, Avhich differs in 

 the number of spores produced in each cell, 

 and in possessing large pi'imary filaments 

 with lateral tuits of dehcate ones, re- 

 sembling those of Sfit/eoclonium (fig. 179, 

 p. 271). 



S. jn-otensiim (PI. 0. fi^. 5). Tufts of 

 filaments 1-36 to 1-60" high, very much 

 branched and elongated ; primary filaments 

 1-1800" in diameter, joints equal or three 

 times as long (Drap. condcnsata, Ilassall). 



S. tenue. Tufts about 1-36" to 1-72" 

 hig'h; filaments 1-21G0" in diam., torulose; 

 set above with tufts of abbreviated brauch- 

 le's {Drap. tenuis, Llass. ) 



<S'. elotuiatum. Filaments very slender, 

 1-2880" in diam.; branches erecto-patent, 

 often opposite, subramulose, fkagelliform ; 

 joints three or five limes as long as broad 

 (jJrap. elong. Ilass.). 



S. nanum. Filaments highly mucous, 

 very slender, sparingly bninched, branches 

 acuminate, not usually ciliate ; cells rather 

 broader than long {Drap. nana, Ilass.). 



]5tbl. Kiitz. Sp. Al,/. 352; Tab. P/ii/c. 

 iii. pis. 1-11; Ilassall, L'r. Ahj. p. 118; 



Thuret, Ann. Sc. Nat. 3. xiv. 223, pi. 18 ; 

 liabenh. Aly. iii. 375. 



_ STIG'MA.— The part of the pistil of An- 

 giospermous Flowering Plants, upon which 

 the pollen rests to produce its pollen-tubes, 

 and where the oi'ifices exist leading to the 

 cavity of the ovary. It is situated either 

 at or near the summit of the style or its 

 branches ; or, when this is absent, it is ses- 

 sile on the ovary. The surface of the stigma 

 is clothed with papilliform or short tubular 

 cells, from which a tenacious secretion 

 exudes at the period when the ovules are 

 prepared to receive the pollen-tubes. At- 

 tached by this adhesive fiuid and often 

 grasped by the papillae the polkm-grains 

 produce theu" tubes, which make their way 

 between the papilhe to descend through 

 the conducting tissue of the style to the 

 placenta (PI. 40. fig. 30). These papilli- 

 form cells in a young state often form 

 favourable subjects for the study of the pro- 

 toplastic cell-contents, and also of the fiuid 

 colouring-matter. The forms of the stigma 

 are exceedingly varied aud sometimes very 

 elegant; and some of those covered with 

 coloured hairs form beautiful microscopic 

 objects. In the Order Oompositos, its cha- 

 racters are used for the systematic divi=:ion 

 of the numerous genera. 



_ STIGM-F'US, Koch.— A genus of Trom- 

 bidiua (Acarina). Legs seven-jointed, ce- 

 phalothorax Avith transverse line ; no eyes. 

 !S. cruentus, very minute. (Koch, Ucbcrs. ; 

 Murray, Fc Ent. 124.) 



STIGMAPH'ORA, Wallich. 



A genus 



of Diatomaceie. 



Char. Frustules free, naviculoid ; valves 

 lanceolate, loculale ; kiculi with central and 

 marginal puncta ; marine. India. 



BiBL. Wallich, Tr. Mic. 8oc. viii. 43; 

 Eabeuht. Ah/, i. 258. 



STIG'MATA OF Animals. See Smra- 



CLES. 



STIGMATIDIUM, Mey.— A genus of 

 Graphidei (Lichenaceous Lichens). Apo- 

 tliecia brownish, punctiform or elongate, 

 immersed, hypothecium colourless, (Leigh- 

 ton, Lich. Flora, 412.) 



STKiONE'MA, Ag. — A supposed genus 

 of Oscillatoriaceiie, founded up(m wliat has 

 proved to be the thallus of a genus of 

 Lichens. See Ephebe. 



STILBA'OEI.— A family of Hyphonwce- 

 tous Fungi, growing upon decaying animal 

 or vegetable matter, or oji bark or leathery 

 leaves. Characterized by a receptacle com- 

 posed of conjoined filamentous or hexagoual 



