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do ourselves an injury in research by assuming mere incidental uses 
as the main purposes for which structures seem to be *' adapted." 
One of these uses in the spines of cactus has occurred to me after 
reading Dr. Newberry's remarks on Fim/s edulis in the last number. 
They break the full force of the sun on the plant, a force it is made 
to endure and not to love, as we know who have learned to cultivate 
it. Plant lovers set out their treasures in summer under "arbors" 
of fish-netting or galvanized wire, and those who have no experience 
would be surprised to find how the moving shadow^s of the twine or 
wire lowers the temperature. A mass of spines on a cactus must 
certainly have the same effect. A cactus does not need much light 
on its epiderm to keep healthy. On the dry mesas along the Un- 
compahgre River I have seen some aggregated masses of Echinocactus 
plmniceus forming dense hemispheres a foot high and as much wide, 
with spines so thoroughly interlaced with spines as to rival the hedge- 
hog, and leaving not a particle of the green surface visible; and there 
are species not caespitose, such as E. pectinatus^ which no one can 
see for spines without cutting apart, and forming a complete protec- 
tion from the hot suns under which they are doomed to live. 
I do not suppose I have yet reached the final purpose of spines in 
a cactus any more than we have the final purpose in the existence of 
the cactus itself, but that one use of cactus spines is to furnish a 
partial shade I feel to be beyond a doubt. 
Thomas Meehan. 
Gyalecta lamprospora, Nyl. — In a recent number of the Regens- 
burg Flora, Dr. Nylander, of Paris, has described a lichen sent him by 
n^e as follows: " Thallus white, opaque, thin; apothecia becoming 
black, superficial, opaque, subrugulose, about 0.5™"^* or less in diameter; 
spores 8, without color, narrowly oblong, muriform-divided o.ioo- 
iic'**'^- long, 0.0 10- II broad, in the middle somewhat constricted, 
paraphyses slender, the epithecium, with the perithecium and the 
lower stratum of the hypothecium, dark colored. Reaction with 
iodine fulvous red. On unknown exotic bark. A marked species of 
a distinct type. Thallus not corticate, all its elements, with the 
conceptacle of the apothecia, fulvous red; the scanty and confusedly 
cellular portion reacting similarly. Gonidia mostly chroolepid, con- 
nected, medium-sized and emitting lichenose hyphoid filaments. 
Younger apothecia obtusely margined, with an impressed disk. 
Thekes pyriform, long stipitate below, spermatia bowed, about 
0.018°^"^- long." 
To this description Dr. Nylander adds: " We have distinctly seen 
each gonidium, and even young gonidia, of this lichen emit from 
^ts walls one and even two filaments, characteristically lichenose. 
It is perfectly evident that these productions are lichenose, and con- 
Jinuations of the wall of the gonidium. What then becomes of 
'symbiosis? for where is here the * fungus ' and where the 'alga ? 
In the lichen there exist only lichenose elements, as is everywhere 
demonstrated. 
f V 
J. w 
collected near Philadelphia, without further indication. But the 
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