28 



ESSENTIALS OF VEGETABLE PHARMACOGNOSY. 



The continuation of the filament, in- lar or linear, and the base or apex may be 

 stead of being along the back, may be truncate, rounded, obtuse, acute or 



pointed. An anther is occasionally 

 doubled upon itself, when it is styled 

 Sinuous (Fig. 112). It may even take the 

 form of a horizontal ring (Fig. 111). 

 This condition is sometimes preceded by 

 the loss of one theca. In any case of 

 curvature, even slight, of the anther, the 

 same is characteristic and of value in 



centrally up through the base and between 

 the thecae (Fig. 107), the Innate form. 

 The lower portions of the thecae may be 

 separated from one another and from the 

 connective (Fig. 108), the Sagittate form. 

 The sagittate condition is sometimes ex- 

 treme, the anthers becoming more or less 

 reniform (Fig. 109) or semi-circular, or 

 they may even become horizontal (Fig, 

 110). This is to be distinguished from the 

 form which is horizontal by versatility 

 (Fig. lOG), by the presence in the latter of 

 the two cells side by side, in the former, 

 end to enil. Rarely the adnate form will 

 possess the connective upon the inner side 

 (next the pistil), when it is Extrorse by 



Attachment, in the normal form being 

 Introrse. 



Besides these variations in the relation 

 of the two parts, each is in itself subject 

 to certain modifications. Some of them 

 will be discussed in connection with ap- 



classification, as exemplified in the vast 

 genus Solanum, where attention to this 

 character is well nigh indispensable. The 

 filament is also sometimes variously 

 curved or reduplicate, and this condition 

 may be permanent, or only temporary, 

 during the early stage of the flower, for 

 the purpose of utilizing the powerful elas- 

 ticity of the filament in promoting some 

 function. 



Inside of the theca develop certain large 

 cells, the Spore Mother Cells, each of 

 which produces a Tetrad of four pollen- 



pendages and exaggerated growth. The ^^^'^^' 0^^^°^"!^ t^e wall of the 

 general form of the filament is subject to ^^lother-cell mostly disappears and leaves 



the grains separate and mobile, while in 

 other cases they cohere in the tetrad or a 

 cluster of tetrads. Large clusters are 

 called Pollinia or Pollen-Masses. The en- 

 tire contents of a theca may form one 

 pollinium or they may be divided into sev- 

 eral. (Figs. 113 and 114). A cluster of 

 pollinia is called a Follinarium. The num- 

 ber of pollinia in a theca is of much 

 diagnostic importance in the Orchidaceae. 

 The characteristics of the individual pol- 



muoh variation which, being character- 

 istic in a given species or genus, requires 

 specification. When cylindrical, either of 

 uniform thickness throughout or regularly 

 tapering, it is Terete. When considerably 

 thickened toward and at the summit, so 

 as to be club-shaped, it is called Clavate. 



When flattened it is Complanate. Lan^r- 



ally Complanate ib so flattened that the 

 edges point toward and from the gynae- 

 ciurn, the broad sides to right and left. 



Dorsally complanate has the edges point- ^^^-^rains are of the utmost value in phar- 

 ni: to ri;;]it and li^ft, the broad sides far- ^f^cognosy as well as in classification (as, 



for instance, in the Acanthaceae), and 

 will be discussed in the division of His- 

 tology. Pollen-grains represent two 

 classes, with characteristic characters, 

 the one adapted for distribution by insect 



ing toward and from the gynaecium, A 

 dorsally complanate filament may have a 

 sharp ridge or keel running along its back, 

 when it is called Carinate or Keeled. If 

 the ridge is less sharp and prominent it is 

 Costate or Ribbed. It may upon the other 

 hand bear a groove, when it is called 

 Channelled, Rarely a filament is Triangu- 

 late in cross-section or otherwise pris- 



agency, the other by that of the wind. 



We must next consider the structural 

 provisions for permitting the escape of the 

 pollen from the thecae or locellae. This 



matic. When tapering from a broad base is commonly by splitting, Dehiscence, 

 to a rather acute apex, it is Subulate or 

 awl-shaped. When very slender or 

 thread-shaped, it is Filiform. When even 



more slender, hair-like, it is Capillary. 



The principal forms of anther are ob- 



long, oval, globular, reniform, quadrangu- face, as in the tomato (Fig. 116), Ventral; 



along a longitudinal line upon each theca, 

 the Suture, 



If the suture is at the back of the an- 

 ther, as in Hyoscyamus (Fig. 115), the de- 

 hiscence is called Dorsal. If upon the 



