ORCHID 



is continued by an axillary bud originating in the axil of 

 one of the leaves. The whole plant is thus built up 

 of branches sympodially united. The lower part of 

 each new axis is prostrate at first and bears only scales. 

 It is known as the rhizome. Later the apex turns 

 upward and bears ordinary leaves. In many the erect 

 portion of the stem becomes thickened into a food 

 reservoir known as a pseudobulb. The pseudohulb 

 itself may consist of several internodes, as in Lfplia. 

 Cattleya. It is then clothed with leaves, at least when 

 young, and bears the scars of the fallen leaves. In 

 other cases only a single internode is thickened. This 

 bears 1 or 2 Ivs. at the summit, but has no leaf-scars. 

 The new shoot which continues the growth of the pla 



ORCHID 



1163 



the 



of. 



bulb. Til. 



clothed with le!l^ . 

 florescence is eith 

 or terminal (Cattl. \ 

 The habit of the 

 upon the rhizome. 

 loose and stragglm] 

 pact in habit. 



if the scales below the pseudo- 

 ith is sho%vn in Figs. 1566 and 

 rked n « and b b, respectively 

 branch with its basal portion 

 lI i...Tti.iii or pseudobulb. In 



I long or short stem 

 ~ I' tiipedium). The in- 

 ' ii.lrobium, Fig. 15«6) 



in a great measure 

 long the plants are 



short they are com- 

 be.'.inies suberect or 



1S67. Cattleya. 



The light and shaded parts, a a and b b, each represent 

 one year's growth. 



vegetable kingdom. The ; 



the sepals and petals, have I"t-ti ■ 



In the monocotyledons tiM • 



whorls of stamens. In tli.- ' ' 

 are fertile. In the Monainli ■ 

 odd stamen of the outer win i 

 like starainodinm il'i--. 1 "' - : ■', 

 mens of the inner \v: 

 1 on each side of rlh - 

 In all the other Oi-.li:!-. ■ \^ . i i :m 

 the od.l stamen of the outer wlioii 

 anther situated at the top of the c 

 The similar two of the inner wl 

 staniinodia. forming the sides n 



showing the uni..ii -f :; |-i..iU . r;-- i:.!--, Im.!i, '. In 

 most of the other uvmr,', .mlv _' "f ili.' -tiL-m:!^ :ire 

 receptive, the thir.l hiin;;' ,1,\ riM|,. ,| nii<i i1m- .mi,, us 

 rost.-llum. In soi,,,- ,-;,ms th,- stiL'i,.,-iti,- surf:,,',- are 



h ' ,, ii,i:ili\ they appear as flat surfaces 



',1' I ,|, pr,ssi,>n 'in the column (Ljeliinese, 



I'l^ I :". , :,ii,| niuny others). In a few cases the 

 Mi^ii...- ai.- HI, .11- ..r less elevated on stalks (Habena- 

 ria). In Sophrouitis they extend partially along two 

 wing-like pro.iections of the column. 

 The odd pistil, the rostellum, is situated above the 



stigmas, separating them from the anther-bed. In the 

 Lseliineae its lower surface is still continuous with the 

 stigmatic surface (Figs. 1570, A, B, r). The principal 

 function of the rostellum is the secretion of a viscid 

 fluid, by means of which 



the pollen masses adhere to ,>,^ ^st 



insects visiting the flowers. 



1568. Cypripedium. 



St, staminodium; a, anther: 



The anther lies above the 

 sion or anther-bed (Fig. 1; 

 2-4 or 8. In nearly all the 

 in masses or poUinia (Fig, 

 pollen masses correspondii 

 cells. Often the viscid st 

 grains is prolonged into a 

 tends beyond the anfh.r n 

 the viscid sul,^taii,-,, s,.,T,,t 

 forms an a.lli,-i\, ,li-k 1,\ : 

 become att.i,-hf,i t,, in-,,,!-. 

 layer of thi- i-,.M,ll.iiii ii^.l 

 of" th., un.hTlvini;- ,',IK. ;,ii, 

 whi.-h l"-.-,,n.,s an:,,- 

 pr..du,T ,,f the ,l,.s 

 the stalls, with its V 

 important parts of t 

 pollen is transporte 

 eross-poUination of 

 mechanism by whic 

 beautifully explaine. 



I 1569. 



Selenipedium caudatum. 



St, stamiuodium; a, anther: 

 s, 3-lobed stigma. 



rostellum, within a depres- 

 rO, a). Its cells vary from 

 Orchids the pollen coheres 



1570, /)), the number of 

 g to the number of anther 

 bstance uniting the pollen 

 stalk (caudicle), which ex- 

 n,l comes into contact with 

 ,■,1 by the rostellum, which 

 iieans of which the pollinia 



In many Orchids the outer 



11,11- I..IIII- ,1 -i:ilk (Stipe), 



"The Vi 



js C. 



tilized bv Insects." 



The relation of the ] 

 is often greatly chang, 

 floral axis. This is c. 

 development, but it s, 

 tubular, inclosing the . 



A. B. Section through the col- 



Column of Cattleya. umn of Cattleya. 



a. aiitliei- ; r. rostellum: p, poUinium: r. rostellum: 



1570. Details of the column of Cattleya. 



near the top of the ovary form the " foot " of the column 

 found in many orchids (Pescatoria, Phaius). When the 

 foot is present the labellnm is attached to its apex, and 

 often the sepals are decurrent upon it, forming a men- 



