134 Miscellaneous. 



On the Structure of the Flower of the Gramincse, the Functions of the 

 Organs of which it is composed, and the Phenomena which accom- 

 pany the act of Fecundation. By M. Bidard. 



The flower of the Gramineae is formed of a two-valved perigoniura 

 (glumella). The outer valve, which is always the larger, is in the 

 form of a keel ; its texture is coarse and parchment-like ; and it 

 embraces the inner valve with its margins all round. The inner 

 valve is almost flat externally ; its tissue is slight and transparent ; 

 at its margins it is folded inwards so as to form two screens, closed 

 above and separated below. On its sides the inner valve is furnished 

 with very numerous hairs. 



The arrangement of these two valves is such that they form by 

 their juxtaposition a completely closed chamber, the closure of which 

 is rendered still more perfect by the hairs of the inner valve. Under 

 such cii'cumstances no foreign body can penetrate into the interior. 

 In this chamber are enclosed the ovary and the organs of fecunda- 

 tion. 



The stamens are three in number, and they occupy two-thirds of 

 the space formed by the union of the two valves. Two of the sta- 

 mens are placed one on each side of the ovar)', and the third is op- 

 posite to it. The filaments do not exceed the ovary in length ; at 

 the base of the filaments, in front of the ovary, two glands (glumel- 

 lulse of botanists), varying in form according to the genus, occur in 

 all the Graminea?. 



The ovary is surmounted by two stigmata, each of which is formed 

 by a principal canal, upon which small canals are inserted laterally, 

 having narrow tubes open at their extremity. 



Phenomena of Fecundation. — The phenomena of fecundation occur 

 when the organs of the flower have attained their full development. 

 In the Graminea) fecundation is instantaneous. It is manifested as 

 follows : — 



The anthers open laterally, become animated by a movement of 

 torsion, and let fall a shower of pollen upon the stigma, which is 

 spread out like a fan ; at this moment the filaments become rapidly 

 elongated ; and by means of this elongation and of their movement 

 of torsion the stamens separate the valves, force a passage, and 

 hang down outside the flower. They are then almost empty. At 

 this period the agriculturist says, " The corn is in flower ;" but this 

 is an error : the fecundation is completed. 



The filaments of the stamens are not arranged in a spiral form, 

 nor are they folded upon themselves. To efl'ect their elongation 

 they require perfectly prepared material ; and this they find in the 

 two glands placed at the base of the ovary : these contain a thick 

 juice, which may be extracted by pricking them with a needle. The 

 glands serve so well for the alimentation of the filaments, that they 

 are emptied when the elongation takes place. 



The pollen of the Gramineaj possesses no trace of a pollinic tube, 

 nor could I in any case observe an ejection of fovilla. AVhen the 

 pollen falls upon the stigma, it attaches itself to the narrow tubes 



