410 



BOTANY 



PART II 



Fig. 343. — Russula rubra. Portion of tlie liymenium. sU, 

 Sub-hymenial layer ; 6, basidia ; s, sterigmata ; sp, .spores ; 

 p, paraphy.ses ; c, a cystid. ■ (x 540.) 



spores. Only a few forms are included in this order. Among the most familiar 



is Axtricularia sambucina 

 (Judas's ear), found on old 

 Elder stems. It has gelatin- 

 ous, daik brown fructifica- 

 tions, which are shell-shaped 

 and bear on their inner sides 

 the basidial hymenium. 



Order 4. Tremellineae 



The basidia are longi- 

 tudinally divided (Fig. 334, 

 B). The hymenium is situ- 

 ated on the upper surface of 

 the fructifications, which are 

 generally gelatinous and irre- 

 gularly lobed or folded. The 

 few genera included in this 

 order are saprophytic on de- 

 caying wood and tree-trunks, 

 on the surface of which the 

 fructifications are produced. 



Order 5. Hymenomycetes (^^' *^) 



The basidia are undivided, and bear four spores at the apices of slender 

 sterigmata (Fig. 343, sjj). In 

 the simplest forms these basidia 

 spring directly from the my- 

 celium, but in the great major- 

 ity of cases fructifications are 

 produced, Avhich bear definite 

 hymenial layers, composed, in 

 addition to the basidia, of para- 

 physes (Fig. 343,^), and also of 

 sterile cystids (c) or club-shaped 

 tubes characterised by their 

 larger diameter and more strong- 

 ly thickened wall. 



Most of the Hymenomy- 

 cetes develop their profusely- 

 branched white mycelium in 

 the humus soil of forests, in 

 decaying Mood, or on dj'ing tree 

 trunks, and produce fructifica- 

 tions, commonly known as toad- 

 stools, protruding from the sul)- 

 stratum. The mycelium of the 

 forms vegetating in the soil 

 spreads farther and farther, and 

 dying in the centre as it ex- 

 hausts the food material of the substratum, occupies continually widening con- 



^7n 



Fii;. 344. — KxdbasiiKum Vaccinii. Transvorse soction 

 llircjugli tliy jieripliery of a stiMii of Vacchiinm ; ep, 

 I'pidi'rniis ; p, eortical pareiiehyiiia ; m, mycelial liyphae ; 

 b', protruding basidia without sterigmata ; h", with 

 rudimei'itary sterigmata ; ?/", with four sjiores. (After 

 WoRONiN, X 620.) 



