98 



THE FLOSAL ENVELOPS, OB PERIANTH. 



ing to the law of alternation of organs ; two sepals arc united in tho 

 lower lip and three in the upper, as seen in the sage and the Labiate 

 Order generally. Labiate flowers are said to be (jaleate or helmeted 

 when the upper lip is concave, as in catmint ; ringent or gaping when 

 the throat or mouth is wide open ; personate or masked when the throat 

 is closed as with a, palate, like the snapdragon. 



484. Orchidaceous, a form of the perianth peculiai' to the Orchis 

 with that large and singular tribe in general. It is a 6-parted double 

 perianth, very irregular, characterized chiefly by its Up (labellum), 

 which is the upper petal (lower by the twisting of the ovary) enlarged 

 and variously deformed. 



Certain reduced forms of the perianth require notice hero : 



485. Pappus {jrdmrog, grandfather, alluding to his gray hairs) is- a 

 term applied to the hair-like calyx of tho florets of the Compositsa and 

 other kindred orders. The florets of this order are collected into 

 heads so compactly that the calyxes have not room for expansion in 

 the ordinary way. The pappus is commonly persistent and often in- 

 creases as the fruit matures, forming a feathery sail to waft away the 

 seed through the air, as in the dandelion and thistle. It varies greatly 

 in form and size, as seen in the cuts, sometimes consisting of scales, 



' sometimes of hairs, again of feathers or bristles. Sometimes it is 

 mounted on a stipe, which is the beak of the fruit. 



831 333 829 330 828 832 



Cypsela (incorrectly called acheuium) of the Composite, with various forms of pappus. 828, 

 Eclipta procumbens, no pappus. 329, Ambrosia trifida. 330,Helianthus grosse-serratus, i>appuB 

 2-awned. 331, Ageratum conizoidcs, pappus of five scales. 332, Mulgedium, capillary pappus 

 — cypsela slightly rostrate. 3-33, Lactuca elongata, rostrate cypsela. 



486. Other keductions. Again, the calyx or the limb of the calyx 

 is reduced to a mere rim, as seen in the TJmbelliferse. In tho amenta- 

 ceous orders the whole perianth diminishes to a shallow cup, as in tho 

 poplar, willow, or altogether disappears, as in the birch, ash, lizard-tail. 

 (264-26Y). 



48*7. Set^, meaning bristles in general, is a term specifically used to 

 denote the reduced perianth of the sedges. In the bog-rush (Scirpus) 

 there is, outside the stamens, a circle of six setse, which doubtless rep- 

 resent a 6-leaved perianth. In the cotton-grass (Eriphorum) tlic setae are 

 multiplied and pei'sistent on the fruit, becoming long and cotton-like. 



