288 Transactions. — Botany. 



portion being often carried up by the pileus and torn into 

 patches or warts as the pileus expands (Plate XXII., fig. 6b). 

 The lower portion of the universal veil remains as a sheath 

 round the base of the stem, and is known as a volva (Plate 

 XXII., fig. 6a). A partial veil is present in some species, 

 which, in the young stage of the fungus, forms a membrane 

 extending from the upper part of the stem to the margin of 

 the pileus (Plate XXII., fig. 12a), thus concealing the gills. 

 As the pileus expands the veil separates from the margin or 

 edge of the pileus, shrinks up, and forms a ring or annulus 

 round the stem (Plate XXII., fig. 6c). In some species both 

 primary and secondary veils are present ; in some forms one 

 or other may be absent, and in the majority of species both 

 are absent from the first. 



The pileus is regular when its form is symmetrical, and 

 the gills radiate equally on all sides from its centre ; excentric 

 when the gills radiate from an excentric point (Plate XXII., 

 fig. 7) ; dimidiate when the stem is absent or nearly so, and 

 the pileus is attached laterally, and projects horizontally from 

 its point of attachment (Plate XXII., fig. 10) ; sessile when 

 the stem is entirely absent ; resupinate when the pileus is 

 attached to the substance on which it is growing, and the gills 

 necessarily point upward, as in primitive types (Plate XXII., 

 fig. 10) ; umbonate when there is a rather pointed projection 

 or boss in the centre or apex of the pileus (Plate XXII., fig. 

 8a) ; gibbous when the boss is broader and blunter than in 

 the umbonate type (Plate XXII., fig. 9a) ; umbilicate when 

 there is a small dimple at the apex of the pileus (Plate XXII., 

 fig. 2a) ; infundibuliform when the pileus is depressed like a 

 funnel (Plate XXII, fig. la) ; striate when evenly and slightly 

 fluted for some distance up from the margin (Plate XXIV., 

 fig. 7) ; sulcate when the ridges are stronger than in the striate 

 type. Many terms, such as "convex," " campanulate," 

 " warted," "glabrous," "viscid," "scaly," &c., are self- 

 explanatory . 



The genera of the Agaricinece are founded to a great ex- 

 tent on the mode of arrangement and structure of the gills. 

 When the gills are grown to the stem, down which they 

 extend for some distance, thinning out to a narrow point, 

 they are said to be decurrent (this is the most primitive type) 

 (Plate XXII., fig. 16) ; adnate when the gills are attached to 

 the stem by their entire breadth, but do not run down the 

 stem (Plate XXII., fig. 2b); adnexed when the gills are 

 slightly rounded off where they touch the stem, so that they 

 only grow to the stem by about half their entire width (Plate 

 XXII., fig. Sb) ; sinuate when the gill is cut out in a curved 

 manner close to the stem, to which it grows only by a small 

 portion of its width (Plate XXII., fig. db) (sinuate differs from 



