Source : Webster's Revised Unabridged Dictionary (1913)

Spinescent \Spi*nes"cent\, a.[L. spinescens, -entis, p. pr. of
   spinescere to know to grow thorny, fr. spina a thorn: cf. F.
   spinescent.] (Bot.)
   Becoming hard and thorny; tapering gradually to a rigid,
   leafless point; armed with spines. --Gray.