Eesting-nucleus OF BOTANICAL TERMS. 



Retrogressive 



plauts to a feebler degree, 

 namely, the reception of oxy- 

 gen, the oxidation of oxidiza- 

 ble matter, and the release of 

 the products of oxidation. See 

 Transpiration. 



RESPIRATOR"? CAV'lTY, see 

 Stomatic Chamber. 



RESPIRATORY CHAM'BER, see 



Stomatic Chamber. 

 RES'TANT, see Persistent. 



REST'ING glSLL, see Resting- 

 spore. 



REST'ING-NU'CLEUS, a nucleus 

 when not in the act of karyo- 

 kinesis. The nuclear filament 

 then exists in the form of gran- 

 ules, or as a network, often 

 with one or more nucleoli. 



REST'ING PE'RIOD, the period 

 during which a plant, seed, or 

 spore remains dormant. Ap- 

 plied mainly to the dormant 

 period of a resting- spore, then 

 also called by some "involu- 

 tion-period." 



REST'ING SPORANGIUM, a term 

 applied by Pringsheim to cer- 

 tain dormant gonidia of Sapro- 

 legnia and related fungi which 

 eventually produce swarm- 

 spores. 



RESTING SPORE, a spore fur- 

 nished with thick walls and 

 able to retain its vitality for a 

 considerable time, and gen- 

 erally requiring the lapse of 

 time, often over winter, before 

 it will germinate; winter-spore; 

 hypnospore; statospore. 



REsT'ING-STAGE, the stage or 

 condition of a plant, bulb, 

 seed, or spore during its dor- 

 mant or resting period. 



RESU'PINATE, upside-down; in- 

 verted; retroverted; reversed. 

 Compare Supine. 



RETICULATE, in the form of 



network, as the veins in the 

 leaves of most plants. 



RETICULATED, see Reticu- 

 late. 



RETICULATED VESSEL, one 

 having thickenings in the 

 form of network. 



RETICULA'TION, any network ; 

 reticulum. 



RETICULUM, a fibrous mem- 

 brane at the base of the pet- 

 ioles in palms (mattulla); the 

 network which pervades the 

 substance of the cell and nu- 

 cleus enclosing the softer por- 

 tions of the protoplasm; any 

 system of filaments or fibres in 

 the form of network. 



RET'lFdRM, see Reticulate. 



RETINACULUM (pi. Retmac'ula), 



(1) the viscid glandular disk 

 derived from the rostellum at 

 the base of the caudicle of a 

 pollinium in orchids by which 

 it is attached to a visiting in- 

 sect (cement-disk of Miiller); 



(2) one of the arms connecting 

 the pollinia of milk-weeds with 

 the corpusculum; (3) the per- 

 sistent indurated hook-like fu- 

 niculus of the seeds in most 

 Acanthacese. 



RET'INERVED, see Reticulate- 

 veined. 



RE'TROFLEXED, see Reflexed. 



RE'TROFRACTED, see Re- 

 fracted. 



RETROGRESSION, see Retro- 

 gressive Metamorphosis. 



RETROGRESSIVE METAM6R'- 

 PHOSlS, the occurrence in the 

 place of organs of the usual 

 character of those belonging 

 to a lower condition or posi- 

 tion, as when pistils become 

 converted into stamens, petals, 

 or leaves; descending meta- 

 morphosis; retrogression; re- 



151 



