Mr. J. Miers on the Calyceracese. 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 fluid 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 achsenia, a similar exudation from the recep- 

 tacle flows between the numerous achsenia, 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, It. Br. ; — Acicarpha, Juss. ; — Cryptocarpha, Cass. — 

 Char, emend. : Involucrum polyphyllum ; foliola 5, lineari- 

 oblonga, insequalia, persistentia, uniserialia, toro parvulo ad- 

 nata ; receptaculum lineari-cylindricum, toro suffultum, paleis 

 obovatis ovario longioribus inter flores onustum. Flores con- 

 similes, superiores nihilominus substeriles. Calycis tubus 

 ovario 5-angulato arete adnatus, limbo libero 4-5-dentato, 

 dentibus parvis, ovatis, obtusiusculis, hyalinis, textura laxa, 

 tubi angulis continuis, demum excrescentibus. Corolla 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, 



