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Mr. J. Miers on the Calyceracez. 401 
rium, is deeply 5-sulcate, the prominent midrib of its five free 
teeth being continuous with its salient angles; at first it is of 
delicately thin texture, and extremely transparent, consisting 
apparently of two integuments with a fiuid or vacant mesodermal 
space between them ; for the one can be made to move loosely over 
the other by pressure. The subsequent increment of the calyx 
seems to arise from the deposition of solid matter (probably de- 
rived from the receptacle) within the mesodermal space: the 
midribs of the calycine leaves seem to acquire the greatest 
amount of increment, becoming lengthened into thick pungent 
spines; the calycine lobes are at the same time expanded into 
the globose nodules that form the bases of the spines ; while the 
external surface of the calycine tube becomes horny and solid, 
the mesodermal space, being much enlarged, is filled with com- 
pact cellular tissue, which dries into a light spongy or pithy 
substance. While this deposition is taking place within the in- 
teguments of the achzenia, a similar exudation from the recep- 
tacle flows between the numerous achznia, and agglutinates 
them, together with the receptacle, into one solid echinate glo- 
bose head, as before described. This appears to be the nature 
of the change in the development of the fruit in Acicarpa. 
There is an evident difference in the growth that takes place 
in the calyx of Acicarpa and in that of Calycera: in the former 
the excrescent spines are shorter, nodose at their base, subulate, 
with a small groove along their inner face; in the development 
of the spines in Calycera the calycine lobes disappear or become 
entirely expanded into divaricated spines of much greater length 
and thickness, subulate and semiterete in form, being flattened 
on their upper surface. The generic features of Acicarpa, as 
here given from my own observations, will be found to differ in 
many essential respects from the characters assigned to it by 
Richard and DeCandolle. 
Acicarpa, R. Br. ;—Acicarpha, Juss. ;—Cryptocarpha, Cass.— 
Char. emend.: Involucrum polyphyllum ; foliola 5, lineari- 
oblonga, inzqualia, persistentia, uniserialia, toro parvulo ad- 
nata; receptaculum lineari-cylindricum, toro suffultum, paleis 
obovatis ovario longioribus inter flores onustum. Fores con- 
similes, superiores nihilominus substeriles. Calycis tubus 
ovario 5-angulato arcte adnatus, Ambo libero 4—5-dentato, 
dentibus parvis, ovatis, obtusiusculis, hyalinis, textura laxa, 
tubi angulis continuis, demum excrescentibus. Corolle tubus 
gracilis, ovario 2-plo et limbo sesquiduplo longior, limbo in- 
fundibuliformi profunde 4—5-partito, laciniis oblongis, obtu- 
siusculis, crassis, sub-3-nerviis. Stamina inclusa ; filamenta 
imo in tubum monadelphum carnosum fauci insertum coalita, 
