Fruit morphology of some species of the Lamiaceae in the flora of Mongolia

Nutlet morphology in the family Lamiaceae was examined using scanning electron microscopy (SEM) to identify distinct characters for 20 species belonging to 12 genera in the subfamilies: Ajugoideae, Scutellarioideae, Nepetoideae and Lamioideae. Nutlet morphology in the family Lamiaceae showed considerable variation in size, color (light orange-yellow, light nut-brown, pale grey, black and all that), shape (subglobose, obovoid, subobovoid, elliptic), surface ornamentation (type I, type II), nutlet apex (rounded, triangle) and base (truncate, acute, rounded). The described types have been collected in the territory of Mongolia. In Lamiaceae two main types can be recognized based on surface ornamentation: sculptured – type I (including 8 species) and smooth – type II (including 12 species). Within these types subtypes were recognized. Type I: Sculptured nutlets are characterized by having oblong, coneshaped and ellipsoid tubercles occuring on all surfaces. The tubercles densely covered with longish mastoid white color in apex and covered by white hairs, with white mastoids under hairs. Five subtypes can be recognized based on the shape of the tubercles: colliculate-reticulate, wrinkled-colliculate-tuberculate, wrinkled-tuberculate, colliculatetuberculate, hairy. Type II: The smooth nutlets may be divided in 4 subtypes: irregularly reticulate, reticulate, undulate, wrinkled-colliculate.


Introduction
The Mint family (Lamiaceae) is one of the largest Angiosperm families, comprising approximately 240 genera and more than 7000 infrageneric taxa distributed throughout the world and economically very important (Harley, 2003).In the flora of Mongolia Lamiaceae is one of the ten largest plant families represented by 89 taxa belonging to 24 genera and four subfamilies (Badamtsetseg, 2010).
Fruit of Lamiaceae is coenobium, thereof named tetraeremum based on nutlets number, and 18 variants based on nutlets forma, 22 variants based on nutlets surface features (Artyushenko, Fedorov, 1986).Fruit of Lamiaceae is uncluded in coenobium group by the fruit classification and has different forms and surface features (Levina, 1987).
Ultrastructure features of nutlets surface can be used in the taxonomy of the genus Nepeta, and selected group of genera represents the branches of the tribe Nepeteae differentiation which took place in the early stages of its evolution (Budantsev, 1993a, b).Nutlet morphology in the Lamiaceae has been proved useful in varying degrees at different levels of the taxonomic hierarchy (Budantsev, Lobova, 1997).Nutlet characters within the genus Nepeta has a taxonomic significance (Kaya, Dirmenci, 2008).

Material and methods
This study is based on nutlets taken from herbarium specimens, mostly from UBU, ALTB and MMNH (Mongolian Museum of Natural History), and original collections made during expeditions to Khentii, Khubsugul, Uvurkhangai, Tov and Dornogovi provinces.For SEM studies nutlets were coated with carbon using a Hitachi E-1010 ion sputter, observed in a Hitachi S-3400N and photographed.All photomicrographs were made at the department of SEM laboratory, National Science Museum, city Deajeon of South Korea.Nutlet color was defined using color chart.Measurements of nutlet were carried out by reiteration 15-20 times under a microscope Olympus BX 40.The nutlet shape and surface ornamentation were studied following Vit Bojnansky, Agata Fargasova (2007), seed morphology descriptions were carried out with the method Joongku Lee et al. (2009).

Results
We studied nutlet morphology of 20 species belonging to 12 genera of Lamiaceae found in Mongolia.Morphological variation of the size, shape, color, surface type, hilum lay of the seeds in Lamiaceae is described below.We wrote seed morphology descriptions for all these 20 species.
Nutlet color varies from light orange-yellow, light nut-brown, medium buff, pale grey, grey nut-brown, light brown, dark brown, red-brown to black.Nutlet shapes vary from obovoid, suboboviod to elliptic, subglobose.Nutlet apex varies from rounded to triangle and base varies from truncate, acute to rounded.Nutlet surface varies from sculptured and smooth to glabrous and covered by hairs.
In Lamiaceae two main types can be recognized based on surface ornamentation: sculptured -type I, and smooth -type II.Within these types subtypes can be recognized.
TYPE I: Sculptured nutlets are characterized by having oblong, cone-shaped and ellipsoid tubercles occur on all surfaces.The tubercles densely covered with longish mastoid white color in apex and covered by white hairs, with white mastoids under hairs.Five subtypes can be recognized based on the shape of the tubercles: Colliculate-reticulate (fig. 1 c, d) covered on all surfaces by hairs and hairs with white mastoids under hairs (Scutellaria grandiflora Sims., S. sieversii Bunge., S. supina L.).

TYPE II:
The smooth nutlets may be divided in 4 subtypes.

Conclusions
We studied the seed morphology of 20 species belonging to 12 genera of family Lamiaceae found in Mongolia and wrote descriptions for them.
Nutlets have obovoid, suboboviod, elliptic, subglobose shapes; surface could be rough and smooth, glabrous and covered by hairs; light orange-yellow, light nut-brown, medium buff, pale grey, grey nut-brown, light brown, dark brown, redbrown, black in color.
We consider that nutlet morphology has varying degrees at subfamily, genera and species levels of the taxonomic hierarchy.Fruit characters are consistent at generic or species level and therefore it is demanded to study nutlet characters of other genus and species of family Lamiaceae.